diff --git a/json.hpp b/json.hpp
index c9af0bed..87475ab3 100644
--- a/json.hpp
+++ b/json.hpp
@@ -1,12 +1,12 @@
 /*
     __ _____ _____ _____
  __|  |   __|     |   | |  JSON for Modern C++
-|  |  |__   |  |  | | | |  version 3.5.0
+|  |  |__   |  |  | | | |  version 3.10.4
 |_____|_____|_____|_|___|  https://github.com/nlohmann/json
 
 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
 SPDX-License-Identifier: MIT
-Copyright (c) 2013-2018 Niels Lohmann <http://nlohmann.me>.
+Copyright (c) 2013-2019 Niels Lohmann <http://nlohmann.me>.
 
 Permission is hereby  granted, free of charge, to any  person obtaining a copy
 of this software and associated  documentation files (the "Software"), to deal
@@ -27,6444 +27,10911 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 */
 
-#ifndef NLOHMANN_JSON_HPP
-#define NLOHMANN_JSON_HPP
+#ifndef INCLUDE_NLOHMANN_JSON_HPP_
+#define INCLUDE_NLOHMANN_JSON_HPP_
 
 #define NLOHMANN_JSON_VERSION_MAJOR 3
-#define NLOHMANN_JSON_VERSION_MINOR 5
-#define NLOHMANN_JSON_VERSION_PATCH 0
+#define NLOHMANN_JSON_VERSION_MINOR 10
+#define NLOHMANN_JSON_VERSION_PATCH 4
 
 #include <algorithm> // all_of, find, for_each
-#include <cassert> // assert
-#include <ciso646> // and, not, or
 #include <cstddef> // nullptr_t, ptrdiff_t, size_t
 #include <functional> // hash, less
 #include <initializer_list> // initializer_list
-#include <iosfwd> // istream, ostream
+#ifndef JSON_NO_IO
+    #include <iosfwd> // istream, ostream
+#endif  // JSON_NO_IO
 #include <iterator> // random_access_iterator_tag
+#include <memory> // unique_ptr
 #include <numeric> // accumulate
 #include <string> // string, stoi, to_string
 #include <utility> // declval, forward, move, pair, swap
+#include <vector> // vector
 
-// #include <nlohmann/json_fwd.hpp>
-#ifndef NLOHMANN_JSON_FWD_HPP
-#define NLOHMANN_JSON_FWD_HPP
+// #include <nlohmann/adl_serializer.hpp>
 
-#include <cstdint> // int64_t, uint64_t
+
+#include <type_traits>
+#include <utility>
+
+// #include <nlohmann/detail/conversions/from_json.hpp>
+
+
+#include <algorithm> // transform
+#include <array> // array
+#include <forward_list> // forward_list
+#include <iterator> // inserter, front_inserter, end
 #include <map> // map
-#include <memory> // allocator
 #include <string> // string
+#include <tuple> // tuple, make_tuple
+#include <type_traits> // is_arithmetic, is_same, is_enum, underlying_type, is_convertible
+#include <unordered_map> // unordered_map
+#include <utility> // pair, declval
+#include <valarray> // valarray
+
+// #include <nlohmann/detail/exceptions.hpp>
+
+
+#include <exception> // exception
+#include <stdexcept> // runtime_error
+#include <string> // to_string
 #include <vector> // vector
 
-/*!
-@brief namespace for Niels Lohmann
-@see https://github.com/nlohmann
-@since version 1.0.0
-*/
-namespace nlohmann
-{
-/*!
-@brief default JSONSerializer template argument
+// #include <nlohmann/detail/value_t.hpp>
 
-This serializer ignores the template arguments and uses ADL
-([argument-dependent lookup](https://en.cppreference.com/w/cpp/language/adl))
-for serialization.
-*/
-template<typename T = void, typename SFINAE = void>
-struct adl_serializer;
 
-template<template<typename U, typename V, typename... Args> class ObjectType =
-         std::map,
-         template<typename U, typename... Args> class ArrayType = std::vector,
-         class StringType = std::string, class BooleanType = bool,
-         class NumberIntegerType = std::int64_t,
-         class NumberUnsignedType = std::uint64_t,
-         class NumberFloatType = double,
-         template<typename U> class AllocatorType = std::allocator,
-         template<typename T, typename SFINAE = void> class JSONSerializer =
-         adl_serializer>
-class basic_json;
+#include <array> // array
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t
+#include <string> // string
+
+namespace nlohmann
+{
+namespace detail
+{
+///////////////////////////
+// JSON type enumeration //
+///////////////////////////
 
 /*!
-@brief JSON Pointer
+@brief the JSON type enumeration
 
-A JSON pointer defines a string syntax for identifying a specific value
-within a JSON document. It can be used with functions `at` and
-`operator[]`. Furthermore, JSON pointers are the base for JSON patches.
+This enumeration collects the different JSON types. It is internally used to
+distinguish the stored values, and the functions @ref basic_json::is_null(),
+@ref basic_json::is_object(), @ref basic_json::is_array(),
+@ref basic_json::is_string(), @ref basic_json::is_boolean(),
+@ref basic_json::is_number() (with @ref basic_json::is_number_integer(),
+@ref basic_json::is_number_unsigned(), and @ref basic_json::is_number_float()),
+@ref basic_json::is_discarded(), @ref basic_json::is_primitive(), and
+@ref basic_json::is_structured() rely on it.
 
-@sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
+@note There are three enumeration entries (number_integer, number_unsigned, and
+number_float), because the library distinguishes these three types for numbers:
+@ref basic_json::number_unsigned_t is used for unsigned integers,
+@ref basic_json::number_integer_t is used for signed integers, and
+@ref basic_json::number_float_t is used for floating-point numbers or to
+approximate integers which do not fit in the limits of their respective type.
 
-@since version 2.0.0
+@sa see @ref basic_json::basic_json(const value_t value_type) -- create a JSON
+value with the default value for a given type
+
+@since version 1.0.0
 */
-template<typename BasicJsonType>
-class json_pointer;
+enum class value_t : std::uint8_t
+{
+    null,             ///< null value
+    object,           ///< object (unordered set of name/value pairs)
+    array,            ///< array (ordered collection of values)
+    string,           ///< string value
+    boolean,          ///< boolean value
+    number_integer,   ///< number value (signed integer)
+    number_unsigned,  ///< number value (unsigned integer)
+    number_float,     ///< number value (floating-point)
+    binary,           ///< binary array (ordered collection of bytes)
+    discarded         ///< discarded by the parser callback function
+};
 
 /*!
-@brief default JSON class
+@brief comparison operator for JSON types
 
-This type is the default specialization of the @ref basic_json class which
-uses the standard template types.
+Returns an ordering that is similar to Python:
+- order: null < boolean < number < object < array < string < binary
+- furthermore, each type is not smaller than itself
+- discarded values are not comparable
+- binary is represented as a b"" string in python and directly comparable to a
+  string; however, making a binary array directly comparable with a string would
+  be surprising behavior in a JSON file.
 
 @since version 1.0.0
 */
-using json = basic_json<>;
+inline bool operator<(const value_t lhs, const value_t rhs) noexcept
+{
+    static constexpr std::array<std::uint8_t, 9> order = {{
+            0 /* null */, 3 /* object */, 4 /* array */, 5 /* string */,
+            1 /* boolean */, 2 /* integer */, 2 /* unsigned */, 2 /* float */,
+            6 /* binary */
+        }
+    };
+
+    const auto l_index = static_cast<std::size_t>(lhs);
+    const auto r_index = static_cast<std::size_t>(rhs);
+    return l_index < order.size() && r_index < order.size() && order[l_index] < order[r_index];
+}
+}  // namespace detail
 }  // namespace nlohmann
 
-#endif
+// #include <nlohmann/detail/string_escape.hpp>
 
+
+#include <string>
 // #include <nlohmann/detail/macro_scope.hpp>
 
 
-// This file contains all internal macro definitions
-// You MUST include macro_unscope.hpp at the end of json.hpp to undef all of them
+#include <utility> // declval, pair
+// #include <nlohmann/thirdparty/hedley/hedley.hpp>
 
-// exclude unsupported compilers
-#if !defined(JSON_SKIP_UNSUPPORTED_COMPILER_CHECK)
-    #if defined(__clang__)
-        #if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
-            #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
-        #endif
-    #elif defined(__GNUC__) && !(defined(__ICC) || defined(__INTEL_COMPILER))
-        #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40800
-            #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
-        #endif
-    #endif
+
+/* Hedley - https://nemequ.github.io/hedley
+ * Created by Evan Nemerson <evan@nemerson.com>
+ *
+ * To the extent possible under law, the author(s) have dedicated all
+ * copyright and related and neighboring rights to this software to
+ * the public domain worldwide. This software is distributed without
+ * any warranty.
+ *
+ * For details, see <http://creativecommons.org/publicdomain/zero/1.0/>.
+ * SPDX-License-Identifier: CC0-1.0
+ */
+
+#if !defined(JSON_HEDLEY_VERSION) || (JSON_HEDLEY_VERSION < 15)
+#if defined(JSON_HEDLEY_VERSION)
+    #undef JSON_HEDLEY_VERSION
 #endif
+#define JSON_HEDLEY_VERSION 15
 
-// disable float-equal warnings on GCC/clang
-#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-    #pragma GCC diagnostic push
-    #pragma GCC diagnostic ignored "-Wfloat-equal"
+#if defined(JSON_HEDLEY_STRINGIFY_EX)
+    #undef JSON_HEDLEY_STRINGIFY_EX
 #endif
+#define JSON_HEDLEY_STRINGIFY_EX(x) #x
 
-// disable documentation warnings on clang
-#if defined(__clang__)
-    #pragma GCC diagnostic push
-    #pragma GCC diagnostic ignored "-Wdocumentation"
+#if defined(JSON_HEDLEY_STRINGIFY)
+    #undef JSON_HEDLEY_STRINGIFY
 #endif
+#define JSON_HEDLEY_STRINGIFY(x) JSON_HEDLEY_STRINGIFY_EX(x)
 
-// allow for portable deprecation warnings
-#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-    #define JSON_DEPRECATED __attribute__((deprecated))
-#elif defined(_MSC_VER)
-    #define JSON_DEPRECATED __declspec(deprecated)
-#else
-    #define JSON_DEPRECATED
+#if defined(JSON_HEDLEY_CONCAT_EX)
+    #undef JSON_HEDLEY_CONCAT_EX
 #endif
+#define JSON_HEDLEY_CONCAT_EX(a,b) a##b
 
-// allow to disable exceptions
-#if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND)) && !defined(JSON_NOEXCEPTION)
-    #define JSON_THROW(exception) throw exception
-    #define JSON_TRY try
-    #define JSON_CATCH(exception) catch(exception)
-    #define JSON_INTERNAL_CATCH(exception) catch(exception)
-#else
-    #define JSON_THROW(exception) std::abort()
-    #define JSON_TRY if(true)
-    #define JSON_CATCH(exception) if(false)
-    #define JSON_INTERNAL_CATCH(exception) if(false)
+#if defined(JSON_HEDLEY_CONCAT)
+    #undef JSON_HEDLEY_CONCAT
 #endif
+#define JSON_HEDLEY_CONCAT(a,b) JSON_HEDLEY_CONCAT_EX(a,b)
 
-// override exception macros
-#if defined(JSON_THROW_USER)
-    #undef JSON_THROW
-    #define JSON_THROW JSON_THROW_USER
+#if defined(JSON_HEDLEY_CONCAT3_EX)
+    #undef JSON_HEDLEY_CONCAT3_EX
 #endif
-#if defined(JSON_TRY_USER)
-    #undef JSON_TRY
-    #define JSON_TRY JSON_TRY_USER
+#define JSON_HEDLEY_CONCAT3_EX(a,b,c) a##b##c
+
+#if defined(JSON_HEDLEY_CONCAT3)
+    #undef JSON_HEDLEY_CONCAT3
 #endif
-#if defined(JSON_CATCH_USER)
-    #undef JSON_CATCH
-    #define JSON_CATCH JSON_CATCH_USER
-    #undef JSON_INTERNAL_CATCH
-    #define JSON_INTERNAL_CATCH JSON_CATCH_USER
+#define JSON_HEDLEY_CONCAT3(a,b,c) JSON_HEDLEY_CONCAT3_EX(a,b,c)
+
+#if defined(JSON_HEDLEY_VERSION_ENCODE)
+    #undef JSON_HEDLEY_VERSION_ENCODE
 #endif
-#if defined(JSON_INTERNAL_CATCH_USER)
-    #undef JSON_INTERNAL_CATCH
-    #define JSON_INTERNAL_CATCH JSON_INTERNAL_CATCH_USER
+#define JSON_HEDLEY_VERSION_ENCODE(major,minor,revision) (((major) * 1000000) + ((minor) * 1000) + (revision))
+
+#if defined(JSON_HEDLEY_VERSION_DECODE_MAJOR)
+    #undef JSON_HEDLEY_VERSION_DECODE_MAJOR
 #endif
+#define JSON_HEDLEY_VERSION_DECODE_MAJOR(version) ((version) / 1000000)
 
-// manual branch prediction
-#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-    #define JSON_LIKELY(x)      __builtin_expect(!!(x), 1)
-    #define JSON_UNLIKELY(x)    __builtin_expect(!!(x), 0)
-#else
-    #define JSON_LIKELY(x)      x
-    #define JSON_UNLIKELY(x)    x
+#if defined(JSON_HEDLEY_VERSION_DECODE_MINOR)
+    #undef JSON_HEDLEY_VERSION_DECODE_MINOR
 #endif
+#define JSON_HEDLEY_VERSION_DECODE_MINOR(version) (((version) % 1000000) / 1000)
 
-// C++ language standard detection
-#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
-    #define JSON_HAS_CPP_17
-    #define JSON_HAS_CPP_14
-#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
-    #define JSON_HAS_CPP_14
+#if defined(JSON_HEDLEY_VERSION_DECODE_REVISION)
+    #undef JSON_HEDLEY_VERSION_DECODE_REVISION
 #endif
+#define JSON_HEDLEY_VERSION_DECODE_REVISION(version) ((version) % 1000)
 
-/*!
-@brief macro to briefly define a mapping between an enum and JSON
-@def NLOHMANN_JSON_SERIALIZE_ENUM
-@since version 3.4.0
-*/
-#define NLOHMANN_JSON_SERIALIZE_ENUM(ENUM_TYPE, ...)                                           \
-    template<typename BasicJsonType>                                                           \
-    inline void to_json(BasicJsonType& j, const ENUM_TYPE& e)                                  \
-    {                                                                                          \
-        static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!");         \
-        static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__;                    \
-        auto it = std::find_if(std::begin(m), std::end(m),                                     \
-                               [e](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
-        {                                                                                      \
-            return ej_pair.first == e;                                                         \
-        });                                                                                    \
-        j = ((it != std::end(m)) ? it : std::begin(m))->second;                                \
-    }                                                                                          \
-    template<typename BasicJsonType>                                                           \
-    inline void from_json(const BasicJsonType& j, ENUM_TYPE& e)                                \
-    {                                                                                          \
-        static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!");         \
-        static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__;                    \
-        auto it = std::find_if(std::begin(m), std::end(m),                                     \
-                               [j](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
-        {                                                                                      \
-            return ej_pair.second == j;                                                        \
-        });                                                                                    \
-        e = ((it != std::end(m)) ? it : std::begin(m))->first;                                 \
-    }
+#if defined(JSON_HEDLEY_GNUC_VERSION)
+    #undef JSON_HEDLEY_GNUC_VERSION
+#endif
+#if defined(__GNUC__) && defined(__GNUC_PATCHLEVEL__)
+    #define JSON_HEDLEY_GNUC_VERSION JSON_HEDLEY_VERSION_ENCODE(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__)
+#elif defined(__GNUC__)
+    #define JSON_HEDLEY_GNUC_VERSION JSON_HEDLEY_VERSION_ENCODE(__GNUC__, __GNUC_MINOR__, 0)
+#endif
 
-// Ugly macros to avoid uglier copy-paste when specializing basic_json. They
-// may be removed in the future once the class is split.
+#if defined(JSON_HEDLEY_GNUC_VERSION_CHECK)
+    #undef JSON_HEDLEY_GNUC_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_GNUC_VERSION)
+    #define JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_GNUC_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-#define NLOHMANN_BASIC_JSON_TPL_DECLARATION                                \
-    template<template<typename, typename, typename...> class ObjectType,   \
-             template<typename, typename...> class ArrayType,              \
-             class StringType, class BooleanType, class NumberIntegerType, \
-             class NumberUnsignedType, class NumberFloatType,              \
-             template<typename> class AllocatorType,                       \
-             template<typename, typename = void> class JSONSerializer>
+#if defined(JSON_HEDLEY_MSVC_VERSION)
+    #undef JSON_HEDLEY_MSVC_VERSION
+#endif
+#if defined(_MSC_FULL_VER) && (_MSC_FULL_VER >= 140000000) && !defined(__ICL)
+    #define JSON_HEDLEY_MSVC_VERSION JSON_HEDLEY_VERSION_ENCODE(_MSC_FULL_VER / 10000000, (_MSC_FULL_VER % 10000000) / 100000, (_MSC_FULL_VER % 100000) / 100)
+#elif defined(_MSC_FULL_VER) && !defined(__ICL)
+    #define JSON_HEDLEY_MSVC_VERSION JSON_HEDLEY_VERSION_ENCODE(_MSC_FULL_VER / 1000000, (_MSC_FULL_VER % 1000000) / 10000, (_MSC_FULL_VER % 10000) / 10)
+#elif defined(_MSC_VER) && !defined(__ICL)
+    #define JSON_HEDLEY_MSVC_VERSION JSON_HEDLEY_VERSION_ENCODE(_MSC_VER / 100, _MSC_VER % 100, 0)
+#endif
 
-#define NLOHMANN_BASIC_JSON_TPL                                            \
-    basic_json<ObjectType, ArrayType, StringType, BooleanType,             \
-    NumberIntegerType, NumberUnsignedType, NumberFloatType,                \
-    AllocatorType, JSONSerializer>
+#if defined(JSON_HEDLEY_MSVC_VERSION_CHECK)
+    #undef JSON_HEDLEY_MSVC_VERSION_CHECK
+#endif
+#if !defined(JSON_HEDLEY_MSVC_VERSION)
+    #define JSON_HEDLEY_MSVC_VERSION_CHECK(major,minor,patch) (0)
+#elif defined(_MSC_VER) && (_MSC_VER >= 1400)
+    #define JSON_HEDLEY_MSVC_VERSION_CHECK(major,minor,patch) (_MSC_FULL_VER >= ((major * 10000000) + (minor * 100000) + (patch)))
+#elif defined(_MSC_VER) && (_MSC_VER >= 1200)
+    #define JSON_HEDLEY_MSVC_VERSION_CHECK(major,minor,patch) (_MSC_FULL_VER >= ((major * 1000000) + (minor * 10000) + (patch)))
+#else
+    #define JSON_HEDLEY_MSVC_VERSION_CHECK(major,minor,patch) (_MSC_VER >= ((major * 100) + (minor)))
+#endif
 
-// #include <nlohmann/detail/meta/cpp_future.hpp>
+#if defined(JSON_HEDLEY_INTEL_VERSION)
+    #undef JSON_HEDLEY_INTEL_VERSION
+#endif
+#if defined(__INTEL_COMPILER) && defined(__INTEL_COMPILER_UPDATE) && !defined(__ICL)
+    #define JSON_HEDLEY_INTEL_VERSION JSON_HEDLEY_VERSION_ENCODE(__INTEL_COMPILER / 100, __INTEL_COMPILER % 100, __INTEL_COMPILER_UPDATE)
+#elif defined(__INTEL_COMPILER) && !defined(__ICL)
+    #define JSON_HEDLEY_INTEL_VERSION JSON_HEDLEY_VERSION_ENCODE(__INTEL_COMPILER / 100, __INTEL_COMPILER % 100, 0)
+#endif
 
+#if defined(JSON_HEDLEY_INTEL_VERSION_CHECK)
+    #undef JSON_HEDLEY_INTEL_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_INTEL_VERSION)
+    #define JSON_HEDLEY_INTEL_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_INTEL_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_INTEL_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-#include <ciso646> // not
-#include <cstddef> // size_t
-#include <type_traits> // conditional, enable_if, false_type, integral_constant, is_constructible, is_integral, is_same, remove_cv, remove_reference, true_type
+#if defined(JSON_HEDLEY_INTEL_CL_VERSION)
+    #undef JSON_HEDLEY_INTEL_CL_VERSION
+#endif
+#if defined(__INTEL_COMPILER) && defined(__INTEL_COMPILER_UPDATE) && defined(__ICL)
+    #define JSON_HEDLEY_INTEL_CL_VERSION JSON_HEDLEY_VERSION_ENCODE(__INTEL_COMPILER, __INTEL_COMPILER_UPDATE, 0)
+#endif
 
-namespace nlohmann
-{
-namespace detail
-{
-// alias templates to reduce boilerplate
-template<bool B, typename T = void>
-using enable_if_t = typename std::enable_if<B, T>::type;
+#if defined(JSON_HEDLEY_INTEL_CL_VERSION_CHECK)
+    #undef JSON_HEDLEY_INTEL_CL_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_INTEL_CL_VERSION)
+    #define JSON_HEDLEY_INTEL_CL_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_INTEL_CL_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_INTEL_CL_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template<typename T>
-using uncvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type;
+#if defined(JSON_HEDLEY_PGI_VERSION)
+    #undef JSON_HEDLEY_PGI_VERSION
+#endif
+#if defined(__PGI) && defined(__PGIC__) && defined(__PGIC_MINOR__) && defined(__PGIC_PATCHLEVEL__)
+    #define JSON_HEDLEY_PGI_VERSION JSON_HEDLEY_VERSION_ENCODE(__PGIC__, __PGIC_MINOR__, __PGIC_PATCHLEVEL__)
+#endif
 
-// implementation of C++14 index_sequence and affiliates
-// source: https://stackoverflow.com/a/32223343
-template<std::size_t... Ints>
-struct index_sequence
-{
-    using type = index_sequence;
-    using value_type = std::size_t;
-    static constexpr std::size_t size() noexcept
-    {
-        return sizeof...(Ints);
-    }
-};
+#if defined(JSON_HEDLEY_PGI_VERSION_CHECK)
+    #undef JSON_HEDLEY_PGI_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_PGI_VERSION)
+    #define JSON_HEDLEY_PGI_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_PGI_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_PGI_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template<class Sequence1, class Sequence2>
-struct merge_and_renumber;
+#if defined(JSON_HEDLEY_SUNPRO_VERSION)
+    #undef JSON_HEDLEY_SUNPRO_VERSION
+#endif
+#if defined(__SUNPRO_C) && (__SUNPRO_C > 0x1000)
+    #define JSON_HEDLEY_SUNPRO_VERSION JSON_HEDLEY_VERSION_ENCODE((((__SUNPRO_C >> 16) & 0xf) * 10) + ((__SUNPRO_C >> 12) & 0xf), (((__SUNPRO_C >> 8) & 0xf) * 10) + ((__SUNPRO_C >> 4) & 0xf), (__SUNPRO_C & 0xf) * 10)
+#elif defined(__SUNPRO_C)
+    #define JSON_HEDLEY_SUNPRO_VERSION JSON_HEDLEY_VERSION_ENCODE((__SUNPRO_C >> 8) & 0xf, (__SUNPRO_C >> 4) & 0xf, (__SUNPRO_C) & 0xf)
+#elif defined(__SUNPRO_CC) && (__SUNPRO_CC > 0x1000)
+    #define JSON_HEDLEY_SUNPRO_VERSION JSON_HEDLEY_VERSION_ENCODE((((__SUNPRO_CC >> 16) & 0xf) * 10) + ((__SUNPRO_CC >> 12) & 0xf), (((__SUNPRO_CC >> 8) & 0xf) * 10) + ((__SUNPRO_CC >> 4) & 0xf), (__SUNPRO_CC & 0xf) * 10)
+#elif defined(__SUNPRO_CC)
+    #define JSON_HEDLEY_SUNPRO_VERSION JSON_HEDLEY_VERSION_ENCODE((__SUNPRO_CC >> 8) & 0xf, (__SUNPRO_CC >> 4) & 0xf, (__SUNPRO_CC) & 0xf)
+#endif
 
-template<std::size_t... I1, std::size_t... I2>
-struct merge_and_renumber<index_sequence<I1...>, index_sequence<I2...>>
-        : index_sequence < I1..., (sizeof...(I1) + I2)... > {};
+#if defined(JSON_HEDLEY_SUNPRO_VERSION_CHECK)
+    #undef JSON_HEDLEY_SUNPRO_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_SUNPRO_VERSION)
+    #define JSON_HEDLEY_SUNPRO_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_SUNPRO_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_SUNPRO_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template<std::size_t N>
-struct make_index_sequence
-    : merge_and_renumber < typename make_index_sequence < N / 2 >::type,
-      typename make_index_sequence < N - N / 2 >::type > {};
+#if defined(JSON_HEDLEY_EMSCRIPTEN_VERSION)
+    #undef JSON_HEDLEY_EMSCRIPTEN_VERSION
+#endif
+#if defined(__EMSCRIPTEN__)
+    #define JSON_HEDLEY_EMSCRIPTEN_VERSION JSON_HEDLEY_VERSION_ENCODE(__EMSCRIPTEN_major__, __EMSCRIPTEN_minor__, __EMSCRIPTEN_tiny__)
+#endif
 
-template<> struct make_index_sequence<0> : index_sequence<> {};
-template<> struct make_index_sequence<1> : index_sequence<0> {};
+#if defined(JSON_HEDLEY_EMSCRIPTEN_VERSION_CHECK)
+    #undef JSON_HEDLEY_EMSCRIPTEN_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_EMSCRIPTEN_VERSION)
+    #define JSON_HEDLEY_EMSCRIPTEN_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_EMSCRIPTEN_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_EMSCRIPTEN_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template<typename... Ts>
-using index_sequence_for = make_index_sequence<sizeof...(Ts)>;
+#if defined(JSON_HEDLEY_ARM_VERSION)
+    #undef JSON_HEDLEY_ARM_VERSION
+#endif
+#if defined(__CC_ARM) && defined(__ARMCOMPILER_VERSION)
+    #define JSON_HEDLEY_ARM_VERSION JSON_HEDLEY_VERSION_ENCODE(__ARMCOMPILER_VERSION / 1000000, (__ARMCOMPILER_VERSION % 1000000) / 10000, (__ARMCOMPILER_VERSION % 10000) / 100)
+#elif defined(__CC_ARM) && defined(__ARMCC_VERSION)
+    #define JSON_HEDLEY_ARM_VERSION JSON_HEDLEY_VERSION_ENCODE(__ARMCC_VERSION / 1000000, (__ARMCC_VERSION % 1000000) / 10000, (__ARMCC_VERSION % 10000) / 100)
+#endif
 
-// dispatch utility (taken from ranges-v3)
-template<unsigned N> struct priority_tag : priority_tag < N - 1 > {};
-template<> struct priority_tag<0> {};
+#if defined(JSON_HEDLEY_ARM_VERSION_CHECK)
+    #undef JSON_HEDLEY_ARM_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_ARM_VERSION)
+    #define JSON_HEDLEY_ARM_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_ARM_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_ARM_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-// taken from ranges-v3
-template<typename T>
-struct static_const
-{
-    static constexpr T value{};
-};
-
-template<typename T>
-constexpr T static_const<T>::value;
-}  // namespace detail
-}  // namespace nlohmann
+#if defined(JSON_HEDLEY_IBM_VERSION)
+    #undef JSON_HEDLEY_IBM_VERSION
+#endif
+#if defined(__ibmxl__)
+    #define JSON_HEDLEY_IBM_VERSION JSON_HEDLEY_VERSION_ENCODE(__ibmxl_version__, __ibmxl_release__, __ibmxl_modification__)
+#elif defined(__xlC__) && defined(__xlC_ver__)
+    #define JSON_HEDLEY_IBM_VERSION JSON_HEDLEY_VERSION_ENCODE(__xlC__ >> 8, __xlC__ & 0xff, (__xlC_ver__ >> 8) & 0xff)
+#elif defined(__xlC__)
+    #define JSON_HEDLEY_IBM_VERSION JSON_HEDLEY_VERSION_ENCODE(__xlC__ >> 8, __xlC__ & 0xff, 0)
+#endif
 
-// #include <nlohmann/detail/meta/type_traits.hpp>
+#if defined(JSON_HEDLEY_IBM_VERSION_CHECK)
+    #undef JSON_HEDLEY_IBM_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_IBM_VERSION)
+    #define JSON_HEDLEY_IBM_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_IBM_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_IBM_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
+#if defined(JSON_HEDLEY_TI_VERSION)
+    #undef JSON_HEDLEY_TI_VERSION
+#endif
+#if \
+    defined(__TI_COMPILER_VERSION__) && \
+    ( \
+      defined(__TMS470__) || defined(__TI_ARM__) || \
+      defined(__MSP430__) || \
+      defined(__TMS320C2000__) \
+    )
+#if (__TI_COMPILER_VERSION__ >= 16000000)
+    #define JSON_HEDLEY_TI_VERSION JSON_HEDLEY_VERSION_ENCODE(__TI_COMPILER_VERSION__ / 1000000, (__TI_COMPILER_VERSION__ % 1000000) / 1000, (__TI_COMPILER_VERSION__ % 1000))
+#endif
+#endif
 
-#include <ciso646> // not
-#include <limits> // numeric_limits
-#include <type_traits> // false_type, is_constructible, is_integral, is_same, true_type
-#include <utility> // declval
+#if defined(JSON_HEDLEY_TI_VERSION_CHECK)
+    #undef JSON_HEDLEY_TI_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_TI_VERSION)
+    #define JSON_HEDLEY_TI_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_TI_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_TI_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-// #include <nlohmann/json_fwd.hpp>
+#if defined(JSON_HEDLEY_TI_CL2000_VERSION)
+    #undef JSON_HEDLEY_TI_CL2000_VERSION
+#endif
+#if defined(__TI_COMPILER_VERSION__) && defined(__TMS320C2000__)
+    #define JSON_HEDLEY_TI_CL2000_VERSION JSON_HEDLEY_VERSION_ENCODE(__TI_COMPILER_VERSION__ / 1000000, (__TI_COMPILER_VERSION__ % 1000000) / 1000, (__TI_COMPILER_VERSION__ % 1000))
+#endif
 
-// #include <nlohmann/detail/iterators/iterator_traits.hpp>
+#if defined(JSON_HEDLEY_TI_CL2000_VERSION_CHECK)
+    #undef JSON_HEDLEY_TI_CL2000_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_TI_CL2000_VERSION)
+    #define JSON_HEDLEY_TI_CL2000_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_TI_CL2000_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_TI_CL2000_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
+#if defined(JSON_HEDLEY_TI_CL430_VERSION)
+    #undef JSON_HEDLEY_TI_CL430_VERSION
+#endif
+#if defined(__TI_COMPILER_VERSION__) && defined(__MSP430__)
+    #define JSON_HEDLEY_TI_CL430_VERSION JSON_HEDLEY_VERSION_ENCODE(__TI_COMPILER_VERSION__ / 1000000, (__TI_COMPILER_VERSION__ % 1000000) / 1000, (__TI_COMPILER_VERSION__ % 1000))
+#endif
 
-#include <iterator> // random_access_iterator_tag
+#if defined(JSON_HEDLEY_TI_CL430_VERSION_CHECK)
+    #undef JSON_HEDLEY_TI_CL430_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_TI_CL430_VERSION)
+    #define JSON_HEDLEY_TI_CL430_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_TI_CL430_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_TI_CL430_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-// #include <nlohmann/detail/meta/void_t.hpp>
+#if defined(JSON_HEDLEY_TI_ARMCL_VERSION)
+    #undef JSON_HEDLEY_TI_ARMCL_VERSION
+#endif
+#if defined(__TI_COMPILER_VERSION__) && (defined(__TMS470__) || defined(__TI_ARM__))
+    #define JSON_HEDLEY_TI_ARMCL_VERSION JSON_HEDLEY_VERSION_ENCODE(__TI_COMPILER_VERSION__ / 1000000, (__TI_COMPILER_VERSION__ % 1000000) / 1000, (__TI_COMPILER_VERSION__ % 1000))
+#endif
 
+#if defined(JSON_HEDLEY_TI_ARMCL_VERSION_CHECK)
+    #undef JSON_HEDLEY_TI_ARMCL_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_TI_ARMCL_VERSION)
+    #define JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_TI_ARMCL_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-namespace nlohmann
-{
-namespace detail
-{
-template <typename ...Ts> struct make_void
-{
-    using type = void;
-};
-template <typename ...Ts> using void_t = typename make_void<Ts...>::type;
-} // namespace detail
-}  // namespace nlohmann
+#if defined(JSON_HEDLEY_TI_CL6X_VERSION)
+    #undef JSON_HEDLEY_TI_CL6X_VERSION
+#endif
+#if defined(__TI_COMPILER_VERSION__) && defined(__TMS320C6X__)
+    #define JSON_HEDLEY_TI_CL6X_VERSION JSON_HEDLEY_VERSION_ENCODE(__TI_COMPILER_VERSION__ / 1000000, (__TI_COMPILER_VERSION__ % 1000000) / 1000, (__TI_COMPILER_VERSION__ % 1000))
+#endif
 
-// #include <nlohmann/detail/meta/cpp_future.hpp>
+#if defined(JSON_HEDLEY_TI_CL6X_VERSION_CHECK)
+    #undef JSON_HEDLEY_TI_CL6X_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_TI_CL6X_VERSION)
+    #define JSON_HEDLEY_TI_CL6X_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_TI_CL6X_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_TI_CL6X_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
+#if defined(JSON_HEDLEY_TI_CL7X_VERSION)
+    #undef JSON_HEDLEY_TI_CL7X_VERSION
+#endif
+#if defined(__TI_COMPILER_VERSION__) && defined(__C7000__)
+    #define JSON_HEDLEY_TI_CL7X_VERSION JSON_HEDLEY_VERSION_ENCODE(__TI_COMPILER_VERSION__ / 1000000, (__TI_COMPILER_VERSION__ % 1000000) / 1000, (__TI_COMPILER_VERSION__ % 1000))
+#endif
 
-namespace nlohmann
-{
-namespace detail
-{
-template <typename It, typename = void>
-struct iterator_types {};
+#if defined(JSON_HEDLEY_TI_CL7X_VERSION_CHECK)
+    #undef JSON_HEDLEY_TI_CL7X_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_TI_CL7X_VERSION)
+    #define JSON_HEDLEY_TI_CL7X_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_TI_CL7X_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_TI_CL7X_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template <typename It>
-struct iterator_types <
-    It,
-    void_t<typename It::difference_type, typename It::value_type, typename It::pointer,
-    typename It::reference, typename It::iterator_category >>
-{
-    using difference_type = typename It::difference_type;
-    using value_type = typename It::value_type;
-    using pointer = typename It::pointer;
-    using reference = typename It::reference;
-    using iterator_category = typename It::iterator_category;
-};
+#if defined(JSON_HEDLEY_TI_CLPRU_VERSION)
+    #undef JSON_HEDLEY_TI_CLPRU_VERSION
+#endif
+#if defined(__TI_COMPILER_VERSION__) && defined(__PRU__)
+    #define JSON_HEDLEY_TI_CLPRU_VERSION JSON_HEDLEY_VERSION_ENCODE(__TI_COMPILER_VERSION__ / 1000000, (__TI_COMPILER_VERSION__ % 1000000) / 1000, (__TI_COMPILER_VERSION__ % 1000))
+#endif
 
-// This is required as some compilers implement std::iterator_traits in a way that
-// doesn't work with SFINAE. See https://github.com/nlohmann/json/issues/1341.
-template <typename T, typename = void>
-struct iterator_traits
-{
-};
+#if defined(JSON_HEDLEY_TI_CLPRU_VERSION_CHECK)
+    #undef JSON_HEDLEY_TI_CLPRU_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_TI_CLPRU_VERSION)
+    #define JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_TI_CLPRU_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template <typename T>
-struct iterator_traits < T, enable_if_t < !std::is_pointer<T>::value >>
-            : iterator_types<T>
-{
-};
+#if defined(JSON_HEDLEY_CRAY_VERSION)
+    #undef JSON_HEDLEY_CRAY_VERSION
+#endif
+#if defined(_CRAYC)
+    #if defined(_RELEASE_PATCHLEVEL)
+        #define JSON_HEDLEY_CRAY_VERSION JSON_HEDLEY_VERSION_ENCODE(_RELEASE_MAJOR, _RELEASE_MINOR, _RELEASE_PATCHLEVEL)
+    #else
+        #define JSON_HEDLEY_CRAY_VERSION JSON_HEDLEY_VERSION_ENCODE(_RELEASE_MAJOR, _RELEASE_MINOR, 0)
+    #endif
+#endif
 
-template <typename T>
-struct iterator_traits<T*, enable_if_t<std::is_object<T>::value>>
-{
-    using iterator_category = std::random_access_iterator_tag;
-    using value_type = T;
-    using difference_type = ptrdiff_t;
-    using pointer = T*;
-    using reference = T&;
-};
-}
-}
+#if defined(JSON_HEDLEY_CRAY_VERSION_CHECK)
+    #undef JSON_HEDLEY_CRAY_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_CRAY_VERSION)
+    #define JSON_HEDLEY_CRAY_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_CRAY_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_CRAY_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-// #include <nlohmann/detail/meta/cpp_future.hpp>
+#if defined(JSON_HEDLEY_IAR_VERSION)
+    #undef JSON_HEDLEY_IAR_VERSION
+#endif
+#if defined(__IAR_SYSTEMS_ICC__)
+    #if __VER__ > 1000
+        #define JSON_HEDLEY_IAR_VERSION JSON_HEDLEY_VERSION_ENCODE((__VER__ / 1000000), ((__VER__ / 1000) % 1000), (__VER__ % 1000))
+    #else
+        #define JSON_HEDLEY_IAR_VERSION JSON_HEDLEY_VERSION_ENCODE(__VER__ / 100, __VER__ % 100, 0)
+    #endif
+#endif
 
-// #include <nlohmann/detail/meta/detected.hpp>
+#if defined(JSON_HEDLEY_IAR_VERSION_CHECK)
+    #undef JSON_HEDLEY_IAR_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_IAR_VERSION)
+    #define JSON_HEDLEY_IAR_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_IAR_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_IAR_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
+#if defined(JSON_HEDLEY_TINYC_VERSION)
+    #undef JSON_HEDLEY_TINYC_VERSION
+#endif
+#if defined(__TINYC__)
+    #define JSON_HEDLEY_TINYC_VERSION JSON_HEDLEY_VERSION_ENCODE(__TINYC__ / 1000, (__TINYC__ / 100) % 10, __TINYC__ % 100)
+#endif
 
-#include <type_traits>
+#if defined(JSON_HEDLEY_TINYC_VERSION_CHECK)
+    #undef JSON_HEDLEY_TINYC_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_TINYC_VERSION)
+    #define JSON_HEDLEY_TINYC_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_TINYC_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_TINYC_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-// #include <nlohmann/detail/meta/void_t.hpp>
+#if defined(JSON_HEDLEY_DMC_VERSION)
+    #undef JSON_HEDLEY_DMC_VERSION
+#endif
+#if defined(__DMC__)
+    #define JSON_HEDLEY_DMC_VERSION JSON_HEDLEY_VERSION_ENCODE(__DMC__ >> 8, (__DMC__ >> 4) & 0xf, __DMC__ & 0xf)
+#endif
 
+#if defined(JSON_HEDLEY_DMC_VERSION_CHECK)
+    #undef JSON_HEDLEY_DMC_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_DMC_VERSION)
+    #define JSON_HEDLEY_DMC_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_DMC_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_DMC_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-// http://en.cppreference.com/w/cpp/experimental/is_detected
-namespace nlohmann
-{
-namespace detail
-{
-struct nonesuch
-{
-    nonesuch() = delete;
-    ~nonesuch() = delete;
-    nonesuch(nonesuch const&) = delete;
-    void operator=(nonesuch const&) = delete;
-};
+#if defined(JSON_HEDLEY_COMPCERT_VERSION)
+    #undef JSON_HEDLEY_COMPCERT_VERSION
+#endif
+#if defined(__COMPCERT_VERSION__)
+    #define JSON_HEDLEY_COMPCERT_VERSION JSON_HEDLEY_VERSION_ENCODE(__COMPCERT_VERSION__ / 10000, (__COMPCERT_VERSION__ / 100) % 100, __COMPCERT_VERSION__ % 100)
+#endif
 
-template <class Default,
-          class AlwaysVoid,
-          template <class...> class Op,
-          class... Args>
-struct detector
-{
-    using value_t = std::false_type;
-    using type = Default;
-};
+#if defined(JSON_HEDLEY_COMPCERT_VERSION_CHECK)
+    #undef JSON_HEDLEY_COMPCERT_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_COMPCERT_VERSION)
+    #define JSON_HEDLEY_COMPCERT_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_COMPCERT_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_COMPCERT_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template <class Default, template <class...> class Op, class... Args>
-struct detector<Default, void_t<Op<Args...>>, Op, Args...>
-{
-    using value_t = std::true_type;
-    using type = Op<Args...>;
-};
+#if defined(JSON_HEDLEY_PELLES_VERSION)
+    #undef JSON_HEDLEY_PELLES_VERSION
+#endif
+#if defined(__POCC__)
+    #define JSON_HEDLEY_PELLES_VERSION JSON_HEDLEY_VERSION_ENCODE(__POCC__ / 100, __POCC__ % 100, 0)
+#endif
 
-template <template <class...> class Op, class... Args>
-using is_detected = typename detector<nonesuch, void, Op, Args...>::value_t;
+#if defined(JSON_HEDLEY_PELLES_VERSION_CHECK)
+    #undef JSON_HEDLEY_PELLES_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_PELLES_VERSION)
+    #define JSON_HEDLEY_PELLES_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_PELLES_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_PELLES_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template <template <class...> class Op, class... Args>
-using detected_t = typename detector<nonesuch, void, Op, Args...>::type;
+#if defined(JSON_HEDLEY_MCST_LCC_VERSION)
+    #undef JSON_HEDLEY_MCST_LCC_VERSION
+#endif
+#if defined(__LCC__) && defined(__LCC_MINOR__)
+    #define JSON_HEDLEY_MCST_LCC_VERSION JSON_HEDLEY_VERSION_ENCODE(__LCC__ / 100, __LCC__ % 100, __LCC_MINOR__)
+#endif
 
-template <class Default, template <class...> class Op, class... Args>
-using detected_or = detector<Default, void, Op, Args...>;
+#if defined(JSON_HEDLEY_MCST_LCC_VERSION_CHECK)
+    #undef JSON_HEDLEY_MCST_LCC_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_MCST_LCC_VERSION)
+    #define JSON_HEDLEY_MCST_LCC_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_MCST_LCC_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_MCST_LCC_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template <class Default, template <class...> class Op, class... Args>
-using detected_or_t = typename detected_or<Default, Op, Args...>::type;
+#if defined(JSON_HEDLEY_GCC_VERSION)
+    #undef JSON_HEDLEY_GCC_VERSION
+#endif
+#if \
+    defined(JSON_HEDLEY_GNUC_VERSION) && \
+    !defined(__clang__) && \
+    !defined(JSON_HEDLEY_INTEL_VERSION) && \
+    !defined(JSON_HEDLEY_PGI_VERSION) && \
+    !defined(JSON_HEDLEY_ARM_VERSION) && \
+    !defined(JSON_HEDLEY_CRAY_VERSION) && \
+    !defined(JSON_HEDLEY_TI_VERSION) && \
+    !defined(JSON_HEDLEY_TI_ARMCL_VERSION) && \
+    !defined(JSON_HEDLEY_TI_CL430_VERSION) && \
+    !defined(JSON_HEDLEY_TI_CL2000_VERSION) && \
+    !defined(JSON_HEDLEY_TI_CL6X_VERSION) && \
+    !defined(JSON_HEDLEY_TI_CL7X_VERSION) && \
+    !defined(JSON_HEDLEY_TI_CLPRU_VERSION) && \
+    !defined(__COMPCERT__) && \
+    !defined(JSON_HEDLEY_MCST_LCC_VERSION)
+    #define JSON_HEDLEY_GCC_VERSION JSON_HEDLEY_GNUC_VERSION
+#endif
 
-template <class Expected, template <class...> class Op, class... Args>
-using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;
+#if defined(JSON_HEDLEY_GCC_VERSION_CHECK)
+    #undef JSON_HEDLEY_GCC_VERSION_CHECK
+#endif
+#if defined(JSON_HEDLEY_GCC_VERSION)
+    #define JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch) (JSON_HEDLEY_GCC_VERSION >= JSON_HEDLEY_VERSION_ENCODE(major, minor, patch))
+#else
+    #define JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch) (0)
+#endif
 
-template <class To, template <class...> class Op, class... Args>
-using is_detected_convertible =
-    std::is_convertible<detected_t<Op, Args...>, To>;
-}  // namespace detail
-}  // namespace nlohmann
+#if defined(JSON_HEDLEY_HAS_ATTRIBUTE)
+    #undef JSON_HEDLEY_HAS_ATTRIBUTE
+#endif
+#if \
+  defined(__has_attribute) && \
+  ( \
+    (!defined(JSON_HEDLEY_IAR_VERSION) || JSON_HEDLEY_IAR_VERSION_CHECK(8,5,9)) \
+  )
+#  define JSON_HEDLEY_HAS_ATTRIBUTE(attribute) __has_attribute(attribute)
+#else
+#  define JSON_HEDLEY_HAS_ATTRIBUTE(attribute) (0)
+#endif
 
-// #include <nlohmann/detail/macro_scope.hpp>
+#if defined(JSON_HEDLEY_GNUC_HAS_ATTRIBUTE)
+    #undef JSON_HEDLEY_GNUC_HAS_ATTRIBUTE
+#endif
+#if defined(__has_attribute)
+    #define JSON_HEDLEY_GNUC_HAS_ATTRIBUTE(attribute,major,minor,patch) JSON_HEDLEY_HAS_ATTRIBUTE(attribute)
+#else
+    #define JSON_HEDLEY_GNUC_HAS_ATTRIBUTE(attribute,major,minor,patch) JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch)
+#endif
 
+#if defined(JSON_HEDLEY_GCC_HAS_ATTRIBUTE)
+    #undef JSON_HEDLEY_GCC_HAS_ATTRIBUTE
+#endif
+#if defined(__has_attribute)
+    #define JSON_HEDLEY_GCC_HAS_ATTRIBUTE(attribute,major,minor,patch) JSON_HEDLEY_HAS_ATTRIBUTE(attribute)
+#else
+    #define JSON_HEDLEY_GCC_HAS_ATTRIBUTE(attribute,major,minor,patch) JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch)
+#endif
 
-namespace nlohmann
-{
-/*!
-@brief detail namespace with internal helper functions
+#if defined(JSON_HEDLEY_HAS_CPP_ATTRIBUTE)
+    #undef JSON_HEDLEY_HAS_CPP_ATTRIBUTE
+#endif
+#if \
+    defined(__has_cpp_attribute) && \
+    defined(__cplusplus) && \
+    (!defined(JSON_HEDLEY_SUNPRO_VERSION) || JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,15,0))
+    #define JSON_HEDLEY_HAS_CPP_ATTRIBUTE(attribute) __has_cpp_attribute(attribute)
+#else
+    #define JSON_HEDLEY_HAS_CPP_ATTRIBUTE(attribute) (0)
+#endif
 
-This namespace collects functions that should not be exposed,
-implementations of some @ref basic_json methods, and meta-programming helpers.
+#if defined(JSON_HEDLEY_HAS_CPP_ATTRIBUTE_NS)
+    #undef JSON_HEDLEY_HAS_CPP_ATTRIBUTE_NS
+#endif
+#if !defined(__cplusplus) || !defined(__has_cpp_attribute)
+    #define JSON_HEDLEY_HAS_CPP_ATTRIBUTE_NS(ns,attribute) (0)
+#elif \
+    !defined(JSON_HEDLEY_PGI_VERSION) && \
+    !defined(JSON_HEDLEY_IAR_VERSION) && \
+    (!defined(JSON_HEDLEY_SUNPRO_VERSION) || JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,15,0)) && \
+    (!defined(JSON_HEDLEY_MSVC_VERSION) || JSON_HEDLEY_MSVC_VERSION_CHECK(19,20,0))
+    #define JSON_HEDLEY_HAS_CPP_ATTRIBUTE_NS(ns,attribute) JSON_HEDLEY_HAS_CPP_ATTRIBUTE(ns::attribute)
+#else
+    #define JSON_HEDLEY_HAS_CPP_ATTRIBUTE_NS(ns,attribute) (0)
+#endif
 
-@since version 2.1.0
-*/
-namespace detail
-{
-/////////////
-// helpers //
-/////////////
+#if defined(JSON_HEDLEY_GNUC_HAS_CPP_ATTRIBUTE)
+    #undef JSON_HEDLEY_GNUC_HAS_CPP_ATTRIBUTE
+#endif
+#if defined(__has_cpp_attribute) && defined(__cplusplus)
+    #define JSON_HEDLEY_GNUC_HAS_CPP_ATTRIBUTE(attribute,major,minor,patch) __has_cpp_attribute(attribute)
+#else
+    #define JSON_HEDLEY_GNUC_HAS_CPP_ATTRIBUTE(attribute,major,minor,patch) JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch)
+#endif
 
-// Note to maintainers:
-//
-// Every trait in this file expects a non CV-qualified type.
-// The only exceptions are in the 'aliases for detected' section
-// (i.e. those of the form: decltype(T::member_function(std::declval<T>())))
-//
-// In this case, T has to be properly CV-qualified to constraint the function arguments
-// (e.g. to_json(BasicJsonType&, const T&))
+#if defined(JSON_HEDLEY_GCC_HAS_CPP_ATTRIBUTE)
+    #undef JSON_HEDLEY_GCC_HAS_CPP_ATTRIBUTE
+#endif
+#if defined(__has_cpp_attribute) && defined(__cplusplus)
+    #define JSON_HEDLEY_GCC_HAS_CPP_ATTRIBUTE(attribute,major,minor,patch) __has_cpp_attribute(attribute)
+#else
+    #define JSON_HEDLEY_GCC_HAS_CPP_ATTRIBUTE(attribute,major,minor,patch) JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template<typename> struct is_basic_json : std::false_type {};
+#if defined(JSON_HEDLEY_HAS_BUILTIN)
+    #undef JSON_HEDLEY_HAS_BUILTIN
+#endif
+#if defined(__has_builtin)
+    #define JSON_HEDLEY_HAS_BUILTIN(builtin) __has_builtin(builtin)
+#else
+    #define JSON_HEDLEY_HAS_BUILTIN(builtin) (0)
+#endif
 
-NLOHMANN_BASIC_JSON_TPL_DECLARATION
-struct is_basic_json<NLOHMANN_BASIC_JSON_TPL> : std::true_type {};
+#if defined(JSON_HEDLEY_GNUC_HAS_BUILTIN)
+    #undef JSON_HEDLEY_GNUC_HAS_BUILTIN
+#endif
+#if defined(__has_builtin)
+    #define JSON_HEDLEY_GNUC_HAS_BUILTIN(builtin,major,minor,patch) __has_builtin(builtin)
+#else
+    #define JSON_HEDLEY_GNUC_HAS_BUILTIN(builtin,major,minor,patch) JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch)
+#endif
 
-//////////////////////////
-// aliases for detected //
-//////////////////////////
+#if defined(JSON_HEDLEY_GCC_HAS_BUILTIN)
+    #undef JSON_HEDLEY_GCC_HAS_BUILTIN
+#endif
+#if defined(__has_builtin)
+    #define JSON_HEDLEY_GCC_HAS_BUILTIN(builtin,major,minor,patch) __has_builtin(builtin)
+#else
+    #define JSON_HEDLEY_GCC_HAS_BUILTIN(builtin,major,minor,patch) JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template <typename T>
-using mapped_type_t = typename T::mapped_type;
+#if defined(JSON_HEDLEY_HAS_FEATURE)
+    #undef JSON_HEDLEY_HAS_FEATURE
+#endif
+#if defined(__has_feature)
+    #define JSON_HEDLEY_HAS_FEATURE(feature) __has_feature(feature)
+#else
+    #define JSON_HEDLEY_HAS_FEATURE(feature) (0)
+#endif
 
-template <typename T>
-using key_type_t = typename T::key_type;
+#if defined(JSON_HEDLEY_GNUC_HAS_FEATURE)
+    #undef JSON_HEDLEY_GNUC_HAS_FEATURE
+#endif
+#if defined(__has_feature)
+    #define JSON_HEDLEY_GNUC_HAS_FEATURE(feature,major,minor,patch) __has_feature(feature)
+#else
+    #define JSON_HEDLEY_GNUC_HAS_FEATURE(feature,major,minor,patch) JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template <typename T>
-using value_type_t = typename T::value_type;
+#if defined(JSON_HEDLEY_GCC_HAS_FEATURE)
+    #undef JSON_HEDLEY_GCC_HAS_FEATURE
+#endif
+#if defined(__has_feature)
+    #define JSON_HEDLEY_GCC_HAS_FEATURE(feature,major,minor,patch) __has_feature(feature)
+#else
+    #define JSON_HEDLEY_GCC_HAS_FEATURE(feature,major,minor,patch) JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template <typename T>
-using difference_type_t = typename T::difference_type;
-
-template <typename T>
-using pointer_t = typename T::pointer;
+#if defined(JSON_HEDLEY_HAS_EXTENSION)
+    #undef JSON_HEDLEY_HAS_EXTENSION
+#endif
+#if defined(__has_extension)
+    #define JSON_HEDLEY_HAS_EXTENSION(extension) __has_extension(extension)
+#else
+    #define JSON_HEDLEY_HAS_EXTENSION(extension) (0)
+#endif
 
-template <typename T>
-using reference_t = typename T::reference;
+#if defined(JSON_HEDLEY_GNUC_HAS_EXTENSION)
+    #undef JSON_HEDLEY_GNUC_HAS_EXTENSION
+#endif
+#if defined(__has_extension)
+    #define JSON_HEDLEY_GNUC_HAS_EXTENSION(extension,major,minor,patch) __has_extension(extension)
+#else
+    #define JSON_HEDLEY_GNUC_HAS_EXTENSION(extension,major,minor,patch) JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template <typename T>
-using iterator_category_t = typename T::iterator_category;
+#if defined(JSON_HEDLEY_GCC_HAS_EXTENSION)
+    #undef JSON_HEDLEY_GCC_HAS_EXTENSION
+#endif
+#if defined(__has_extension)
+    #define JSON_HEDLEY_GCC_HAS_EXTENSION(extension,major,minor,patch) __has_extension(extension)
+#else
+    #define JSON_HEDLEY_GCC_HAS_EXTENSION(extension,major,minor,patch) JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template <typename T>
-using iterator_t = typename T::iterator;
+#if defined(JSON_HEDLEY_HAS_DECLSPEC_ATTRIBUTE)
+    #undef JSON_HEDLEY_HAS_DECLSPEC_ATTRIBUTE
+#endif
+#if defined(__has_declspec_attribute)
+    #define JSON_HEDLEY_HAS_DECLSPEC_ATTRIBUTE(attribute) __has_declspec_attribute(attribute)
+#else
+    #define JSON_HEDLEY_HAS_DECLSPEC_ATTRIBUTE(attribute) (0)
+#endif
 
-template <typename T, typename... Args>
-using to_json_function = decltype(T::to_json(std::declval<Args>()...));
+#if defined(JSON_HEDLEY_GNUC_HAS_DECLSPEC_ATTRIBUTE)
+    #undef JSON_HEDLEY_GNUC_HAS_DECLSPEC_ATTRIBUTE
+#endif
+#if defined(__has_declspec_attribute)
+    #define JSON_HEDLEY_GNUC_HAS_DECLSPEC_ATTRIBUTE(attribute,major,minor,patch) __has_declspec_attribute(attribute)
+#else
+    #define JSON_HEDLEY_GNUC_HAS_DECLSPEC_ATTRIBUTE(attribute,major,minor,patch) JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template <typename T, typename... Args>
-using from_json_function = decltype(T::from_json(std::declval<Args>()...));
+#if defined(JSON_HEDLEY_GCC_HAS_DECLSPEC_ATTRIBUTE)
+    #undef JSON_HEDLEY_GCC_HAS_DECLSPEC_ATTRIBUTE
+#endif
+#if defined(__has_declspec_attribute)
+    #define JSON_HEDLEY_GCC_HAS_DECLSPEC_ATTRIBUTE(attribute,major,minor,patch) __has_declspec_attribute(attribute)
+#else
+    #define JSON_HEDLEY_GCC_HAS_DECLSPEC_ATTRIBUTE(attribute,major,minor,patch) JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template <typename T, typename U>
-using get_template_function = decltype(std::declval<T>().template get<U>());
+#if defined(JSON_HEDLEY_HAS_WARNING)
+    #undef JSON_HEDLEY_HAS_WARNING
+#endif
+#if defined(__has_warning)
+    #define JSON_HEDLEY_HAS_WARNING(warning) __has_warning(warning)
+#else
+    #define JSON_HEDLEY_HAS_WARNING(warning) (0)
+#endif
 
-// trait checking if JSONSerializer<T>::from_json(json const&, udt&) exists
-template <typename BasicJsonType, typename T, typename = void>
-struct has_from_json : std::false_type {};
+#if defined(JSON_HEDLEY_GNUC_HAS_WARNING)
+    #undef JSON_HEDLEY_GNUC_HAS_WARNING
+#endif
+#if defined(__has_warning)
+    #define JSON_HEDLEY_GNUC_HAS_WARNING(warning,major,minor,patch) __has_warning(warning)
+#else
+    #define JSON_HEDLEY_GNUC_HAS_WARNING(warning,major,minor,patch) JSON_HEDLEY_GNUC_VERSION_CHECK(major,minor,patch)
+#endif
 
-template <typename BasicJsonType, typename T>
-struct has_from_json<BasicJsonType, T,
-           enable_if_t<not is_basic_json<T>::value>>
-{
-    using serializer = typename BasicJsonType::template json_serializer<T, void>;
+#if defined(JSON_HEDLEY_GCC_HAS_WARNING)
+    #undef JSON_HEDLEY_GCC_HAS_WARNING
+#endif
+#if defined(__has_warning)
+    #define JSON_HEDLEY_GCC_HAS_WARNING(warning,major,minor,patch) __has_warning(warning)
+#else
+    #define JSON_HEDLEY_GCC_HAS_WARNING(warning,major,minor,patch) JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch)
+#endif
 
-    static constexpr bool value =
-        is_detected_exact<void, from_json_function, serializer,
-        const BasicJsonType&, T&>::value;
-};
+#if \
+    (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || \
+    defined(__clang__) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,0,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0) || \
+    JSON_HEDLEY_PGI_VERSION_CHECK(18,4,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,7,0) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(2,0,1) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,1,0) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,0,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    JSON_HEDLEY_CRAY_VERSION_CHECK(5,0,0) || \
+    JSON_HEDLEY_TINYC_VERSION_CHECK(0,9,17) || \
+    JSON_HEDLEY_SUNPRO_VERSION_CHECK(8,0,0) || \
+    (JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) && defined(__C99_PRAGMA_OPERATOR))
+    #define JSON_HEDLEY_PRAGMA(value) _Pragma(#value)
+#elif JSON_HEDLEY_MSVC_VERSION_CHECK(15,0,0)
+    #define JSON_HEDLEY_PRAGMA(value) __pragma(value)
+#else
+    #define JSON_HEDLEY_PRAGMA(value)
+#endif
 
-// This trait checks if JSONSerializer<T>::from_json(json const&) exists
-// this overload is used for non-default-constructible user-defined-types
-template <typename BasicJsonType, typename T, typename = void>
-struct has_non_default_from_json : std::false_type {};
+#if defined(JSON_HEDLEY_DIAGNOSTIC_PUSH)
+    #undef JSON_HEDLEY_DIAGNOSTIC_PUSH
+#endif
+#if defined(JSON_HEDLEY_DIAGNOSTIC_POP)
+    #undef JSON_HEDLEY_DIAGNOSTIC_POP
+#endif
+#if defined(__clang__)
+    #define JSON_HEDLEY_DIAGNOSTIC_PUSH _Pragma("clang diagnostic push")
+    #define JSON_HEDLEY_DIAGNOSTIC_POP _Pragma("clang diagnostic pop")
+#elif JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_PUSH _Pragma("warning(push)")
+    #define JSON_HEDLEY_DIAGNOSTIC_POP _Pragma("warning(pop)")
+#elif JSON_HEDLEY_GCC_VERSION_CHECK(4,6,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
+    #define JSON_HEDLEY_DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
+#elif \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(15,0,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_PUSH __pragma(warning(push))
+    #define JSON_HEDLEY_DIAGNOSTIC_POP __pragma(warning(pop))
+#elif JSON_HEDLEY_ARM_VERSION_CHECK(5,6,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_PUSH _Pragma("push")
+    #define JSON_HEDLEY_DIAGNOSTIC_POP _Pragma("pop")
+#elif \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,4,0) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(8,1,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_PUSH _Pragma("diag_push")
+    #define JSON_HEDLEY_DIAGNOSTIC_POP _Pragma("diag_pop")
+#elif JSON_HEDLEY_PELLES_VERSION_CHECK(2,90,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_PUSH _Pragma("warning(push)")
+    #define JSON_HEDLEY_DIAGNOSTIC_POP _Pragma("warning(pop)")
+#else
+    #define JSON_HEDLEY_DIAGNOSTIC_PUSH
+    #define JSON_HEDLEY_DIAGNOSTIC_POP
+#endif
 
-template<typename BasicJsonType, typename T>
-struct has_non_default_from_json<BasicJsonType, T, enable_if_t<not is_basic_json<T>::value>>
-{
-    using serializer = typename BasicJsonType::template json_serializer<T, void>;
+/* JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_ is for
+   HEDLEY INTERNAL USE ONLY.  API subject to change without notice. */
+#if defined(JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_)
+    #undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_
+#endif
+#if defined(__cplusplus)
+#  if JSON_HEDLEY_HAS_WARNING("-Wc++98-compat")
+#    if JSON_HEDLEY_HAS_WARNING("-Wc++17-extensions")
+#      if JSON_HEDLEY_HAS_WARNING("-Wc++1z-extensions")
+#        define JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_(xpr) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    _Pragma("clang diagnostic ignored \"-Wc++98-compat\"") \
+    _Pragma("clang diagnostic ignored \"-Wc++17-extensions\"") \
+    _Pragma("clang diagnostic ignored \"-Wc++1z-extensions\"") \
+    xpr \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#      else
+#        define JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_(xpr) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    _Pragma("clang diagnostic ignored \"-Wc++98-compat\"") \
+    _Pragma("clang diagnostic ignored \"-Wc++17-extensions\"") \
+    xpr \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#      endif
+#    else
+#      define JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_(xpr) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    _Pragma("clang diagnostic ignored \"-Wc++98-compat\"") \
+    xpr \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#    endif
+#  endif
+#endif
+#if !defined(JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_(x) x
+#endif
 
-    static constexpr bool value =
-        is_detected_exact<T, from_json_function, serializer,
-        const BasicJsonType&>::value;
-};
+#if defined(JSON_HEDLEY_CONST_CAST)
+    #undef JSON_HEDLEY_CONST_CAST
+#endif
+#if defined(__cplusplus)
+#  define JSON_HEDLEY_CONST_CAST(T, expr) (const_cast<T>(expr))
+#elif \
+  JSON_HEDLEY_HAS_WARNING("-Wcast-qual") || \
+  JSON_HEDLEY_GCC_VERSION_CHECK(4,6,0) || \
+  JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0)
+#  define JSON_HEDLEY_CONST_CAST(T, expr) (__extension__ ({ \
+        JSON_HEDLEY_DIAGNOSTIC_PUSH \
+        JSON_HEDLEY_DIAGNOSTIC_DISABLE_CAST_QUAL \
+        ((T) (expr)); \
+        JSON_HEDLEY_DIAGNOSTIC_POP \
+    }))
+#else
+#  define JSON_HEDLEY_CONST_CAST(T, expr) ((T) (expr))
+#endif
 
-// This trait checks if BasicJsonType::json_serializer<T>::to_json exists
-// Do not evaluate the trait when T is a basic_json type, to avoid template instantiation infinite recursion.
-template <typename BasicJsonType, typename T, typename = void>
-struct has_to_json : std::false_type {};
+#if defined(JSON_HEDLEY_REINTERPRET_CAST)
+    #undef JSON_HEDLEY_REINTERPRET_CAST
+#endif
+#if defined(__cplusplus)
+    #define JSON_HEDLEY_REINTERPRET_CAST(T, expr) (reinterpret_cast<T>(expr))
+#else
+    #define JSON_HEDLEY_REINTERPRET_CAST(T, expr) ((T) (expr))
+#endif
 
-template <typename BasicJsonType, typename T>
-struct has_to_json<BasicJsonType, T, enable_if_t<not is_basic_json<T>::value>>
-{
-    using serializer = typename BasicJsonType::template json_serializer<T, void>;
+#if defined(JSON_HEDLEY_STATIC_CAST)
+    #undef JSON_HEDLEY_STATIC_CAST
+#endif
+#if defined(__cplusplus)
+    #define JSON_HEDLEY_STATIC_CAST(T, expr) (static_cast<T>(expr))
+#else
+    #define JSON_HEDLEY_STATIC_CAST(T, expr) ((T) (expr))
+#endif
 
-    static constexpr bool value =
-        is_detected_exact<void, to_json_function, serializer, BasicJsonType&,
-        T>::value;
-};
+#if defined(JSON_HEDLEY_CPP_CAST)
+    #undef JSON_HEDLEY_CPP_CAST
+#endif
+#if defined(__cplusplus)
+#  if JSON_HEDLEY_HAS_WARNING("-Wold-style-cast")
+#    define JSON_HEDLEY_CPP_CAST(T, expr) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    _Pragma("clang diagnostic ignored \"-Wold-style-cast\"") \
+    ((T) (expr)) \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#  elif JSON_HEDLEY_IAR_VERSION_CHECK(8,3,0)
+#    define JSON_HEDLEY_CPP_CAST(T, expr) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    _Pragma("diag_suppress=Pe137") \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#  else
+#    define JSON_HEDLEY_CPP_CAST(T, expr) ((T) (expr))
+#  endif
+#else
+#  define JSON_HEDLEY_CPP_CAST(T, expr) (expr)
+#endif
 
+#if defined(JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED)
+    #undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED
+#endif
+#if JSON_HEDLEY_HAS_WARNING("-Wdeprecated-declarations")
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("clang diagnostic ignored \"-Wdeprecated-declarations\"")
+#elif JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("warning(disable:1478 1786)")
+#elif JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED __pragma(warning(disable:1478 1786))
+#elif JSON_HEDLEY_PGI_VERSION_CHECK(20,7,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("diag_suppress 1215,1216,1444,1445")
+#elif JSON_HEDLEY_PGI_VERSION_CHECK(17,10,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("diag_suppress 1215,1444")
+#elif JSON_HEDLEY_GCC_VERSION_CHECK(4,3,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
+#elif JSON_HEDLEY_MSVC_VERSION_CHECK(15,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED __pragma(warning(disable:4996))
+#elif JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("diag_suppress 1215,1444")
+#elif \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+    (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("diag_suppress 1291,1718")
+#elif JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,13,0) && !defined(__cplusplus)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("error_messages(off,E_DEPRECATED_ATT,E_DEPRECATED_ATT_MESS)")
+#elif JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,13,0) && defined(__cplusplus)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("error_messages(off,symdeprecated,symdeprecated2)")
+#elif JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("diag_suppress=Pe1444,Pe1215")
+#elif JSON_HEDLEY_PELLES_VERSION_CHECK(2,90,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED _Pragma("warn(disable:2241)")
+#else
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED
+#endif
 
-///////////////////
-// is_ functions //
-///////////////////
+#if defined(JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS)
+    #undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS
+#endif
+#if JSON_HEDLEY_HAS_WARNING("-Wunknown-pragmas")
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS _Pragma("clang diagnostic ignored \"-Wunknown-pragmas\"")
+#elif JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS _Pragma("warning(disable:161)")
+#elif JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS __pragma(warning(disable:161))
+#elif JSON_HEDLEY_PGI_VERSION_CHECK(17,10,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS _Pragma("diag_suppress 1675")
+#elif JSON_HEDLEY_GCC_VERSION_CHECK(4,3,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS _Pragma("GCC diagnostic ignored \"-Wunknown-pragmas\"")
+#elif JSON_HEDLEY_MSVC_VERSION_CHECK(15,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS __pragma(warning(disable:4068))
+#elif \
+    JSON_HEDLEY_TI_VERSION_CHECK(16,9,0) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(8,0,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,3,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS _Pragma("diag_suppress 163")
+#elif JSON_HEDLEY_TI_CL6X_VERSION_CHECK(8,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS _Pragma("diag_suppress 163")
+#elif JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS _Pragma("diag_suppress=Pe161")
+#elif JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS _Pragma("diag_suppress 161")
+#else
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS
+#endif
 
-template <typename T, typename = void>
-struct is_iterator_traits : std::false_type {};
+#if defined(JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES)
+    #undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES
+#endif
+#if JSON_HEDLEY_HAS_WARNING("-Wunknown-attributes")
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("clang diagnostic ignored \"-Wunknown-attributes\"")
+#elif JSON_HEDLEY_GCC_VERSION_CHECK(4,6,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
+#elif JSON_HEDLEY_INTEL_VERSION_CHECK(17,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("warning(disable:1292)")
+#elif JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES __pragma(warning(disable:1292))
+#elif JSON_HEDLEY_MSVC_VERSION_CHECK(19,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES __pragma(warning(disable:5030))
+#elif JSON_HEDLEY_PGI_VERSION_CHECK(20,7,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("diag_suppress 1097,1098")
+#elif JSON_HEDLEY_PGI_VERSION_CHECK(17,10,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("diag_suppress 1097")
+#elif JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,14,0) && defined(__cplusplus)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("error_messages(off,attrskipunsup)")
+#elif \
+    JSON_HEDLEY_TI_VERSION_CHECK(18,1,0) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(8,3,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("diag_suppress 1173")
+#elif JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("diag_suppress=Pe1097")
+#elif JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES _Pragma("diag_suppress 1097")
+#else
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES
+#endif
 
-template <typename T>
-struct is_iterator_traits<iterator_traits<T>>
-{
-  private:
-    using traits = iterator_traits<T>;
+#if defined(JSON_HEDLEY_DIAGNOSTIC_DISABLE_CAST_QUAL)
+    #undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_CAST_QUAL
+#endif
+#if JSON_HEDLEY_HAS_WARNING("-Wcast-qual")
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_CAST_QUAL _Pragma("clang diagnostic ignored \"-Wcast-qual\"")
+#elif JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_CAST_QUAL _Pragma("warning(disable:2203 2331)")
+#elif JSON_HEDLEY_GCC_VERSION_CHECK(3,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_CAST_QUAL _Pragma("GCC diagnostic ignored \"-Wcast-qual\"")
+#else
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_CAST_QUAL
+#endif
 
-  public:
-    static constexpr auto value =
-        is_detected<value_type_t, traits>::value &&
-        is_detected<difference_type_t, traits>::value &&
-        is_detected<pointer_t, traits>::value &&
-        is_detected<iterator_category_t, traits>::value &&
-        is_detected<reference_t, traits>::value;
-};
+#if defined(JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNUSED_FUNCTION)
+    #undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNUSED_FUNCTION
+#endif
+#if JSON_HEDLEY_HAS_WARNING("-Wunused-function")
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNUSED_FUNCTION _Pragma("clang diagnostic ignored \"-Wunused-function\"")
+#elif JSON_HEDLEY_GCC_VERSION_CHECK(3,4,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNUSED_FUNCTION _Pragma("GCC diagnostic ignored \"-Wunused-function\"")
+#elif JSON_HEDLEY_MSVC_VERSION_CHECK(1,0,0)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNUSED_FUNCTION __pragma(warning(disable:4505))
+#elif JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNUSED_FUNCTION _Pragma("diag_suppress 3142")
+#else
+    #define JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNUSED_FUNCTION
+#endif
 
-// source: https://stackoverflow.com/a/37193089/4116453
+#if defined(JSON_HEDLEY_DEPRECATED)
+    #undef JSON_HEDLEY_DEPRECATED
+#endif
+#if defined(JSON_HEDLEY_DEPRECATED_FOR)
+    #undef JSON_HEDLEY_DEPRECATED_FOR
+#endif
+#if \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(14,0,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_DEPRECATED(since) __declspec(deprecated("Since " # since))
+    #define JSON_HEDLEY_DEPRECATED_FOR(since, replacement) __declspec(deprecated("Since " #since "; use " #replacement))
+#elif \
+    (JSON_HEDLEY_HAS_EXTENSION(attribute_deprecated_with_message) && !defined(JSON_HEDLEY_IAR_VERSION)) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(4,5,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(5,6,0) || \
+    JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,13,0) || \
+    JSON_HEDLEY_PGI_VERSION_CHECK(17,10,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(18,1,0) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(18,1,0) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(8,3,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,3,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_DEPRECATED(since) __attribute__((__deprecated__("Since " #since)))
+    #define JSON_HEDLEY_DEPRECATED_FOR(since, replacement) __attribute__((__deprecated__("Since " #since "; use " #replacement)))
+#elif defined(__cplusplus) && (__cplusplus >= 201402L)
+    #define JSON_HEDLEY_DEPRECATED(since) JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[deprecated("Since " #since)]])
+    #define JSON_HEDLEY_DEPRECATED_FOR(since, replacement) JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[deprecated("Since " #since "; use " #replacement)]])
+#elif \
+    JSON_HEDLEY_HAS_ATTRIBUTE(deprecated) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,1,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+    (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10) || \
+    JSON_HEDLEY_IAR_VERSION_CHECK(8,10,0)
+    #define JSON_HEDLEY_DEPRECATED(since) __attribute__((__deprecated__))
+    #define JSON_HEDLEY_DEPRECATED_FOR(since, replacement) __attribute__((__deprecated__))
+#elif \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(13,10,0) || \
+    JSON_HEDLEY_PELLES_VERSION_CHECK(6,50,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_DEPRECATED(since) __declspec(deprecated)
+    #define JSON_HEDLEY_DEPRECATED_FOR(since, replacement) __declspec(deprecated)
+#elif JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0)
+    #define JSON_HEDLEY_DEPRECATED(since) _Pragma("deprecated")
+    #define JSON_HEDLEY_DEPRECATED_FOR(since, replacement) _Pragma("deprecated")
+#else
+    #define JSON_HEDLEY_DEPRECATED(since)
+    #define JSON_HEDLEY_DEPRECATED_FOR(since, replacement)
+#endif
 
-template <typename T, typename = void>
-struct is_complete_type : std::false_type {};
+#if defined(JSON_HEDLEY_UNAVAILABLE)
+    #undef JSON_HEDLEY_UNAVAILABLE
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(warning) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(4,3,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_UNAVAILABLE(available_since) __attribute__((__warning__("Not available until " #available_since)))
+#else
+    #define JSON_HEDLEY_UNAVAILABLE(available_since)
+#endif
 
-template <typename T>
-struct is_complete_type<T, decltype(void(sizeof(T)))> : std::true_type {};
+#if defined(JSON_HEDLEY_WARN_UNUSED_RESULT)
+    #undef JSON_HEDLEY_WARN_UNUSED_RESULT
+#endif
+#if defined(JSON_HEDLEY_WARN_UNUSED_RESULT_MSG)
+    #undef JSON_HEDLEY_WARN_UNUSED_RESULT_MSG
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(warn_unused_result) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,4,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+    (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    (JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,15,0) && defined(__cplusplus)) || \
+    JSON_HEDLEY_PGI_VERSION_CHECK(17,10,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT __attribute__((__warn_unused_result__))
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT_MSG(msg) __attribute__((__warn_unused_result__))
+#elif (JSON_HEDLEY_HAS_CPP_ATTRIBUTE(nodiscard) >= 201907L)
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[nodiscard]])
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT_MSG(msg) JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[nodiscard(msg)]])
+#elif JSON_HEDLEY_HAS_CPP_ATTRIBUTE(nodiscard)
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[nodiscard]])
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT_MSG(msg) JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[nodiscard]])
+#elif defined(_Check_return_) /* SAL */
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT _Check_return_
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT_MSG(msg) _Check_return_
+#else
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT
+    #define JSON_HEDLEY_WARN_UNUSED_RESULT_MSG(msg)
+#endif
 
-template <typename BasicJsonType, typename CompatibleObjectType,
-          typename = void>
-struct is_compatible_object_type_impl : std::false_type {};
+#if defined(JSON_HEDLEY_SENTINEL)
+    #undef JSON_HEDLEY_SENTINEL
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(sentinel) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(4,0,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(5,4,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_SENTINEL(position) __attribute__((__sentinel__(position)))
+#else
+    #define JSON_HEDLEY_SENTINEL(position)
+#endif
 
-template <typename BasicJsonType, typename CompatibleObjectType>
-struct is_compatible_object_type_impl <
-    BasicJsonType, CompatibleObjectType,
-    enable_if_t<is_detected<mapped_type_t, CompatibleObjectType>::value and
-    is_detected<key_type_t, CompatibleObjectType>::value >>
-{
+#if defined(JSON_HEDLEY_NO_RETURN)
+    #undef JSON_HEDLEY_NO_RETURN
+#endif
+#if JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0)
+    #define JSON_HEDLEY_NO_RETURN __noreturn
+#elif \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_NO_RETURN __attribute__((__noreturn__))
+#elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
+    #define JSON_HEDLEY_NO_RETURN _Noreturn
+#elif defined(__cplusplus) && (__cplusplus >= 201103L)
+    #define JSON_HEDLEY_NO_RETURN JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[noreturn]])
+#elif \
+    JSON_HEDLEY_HAS_ATTRIBUTE(noreturn) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,2,0) || \
+    JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,11,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+    (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    JSON_HEDLEY_IAR_VERSION_CHECK(8,10,0)
+    #define JSON_HEDLEY_NO_RETURN __attribute__((__noreturn__))
+#elif JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,10,0)
+    #define JSON_HEDLEY_NO_RETURN _Pragma("does_not_return")
+#elif \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(13,10,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_NO_RETURN __declspec(noreturn)
+#elif JSON_HEDLEY_TI_CL6X_VERSION_CHECK(6,0,0) && defined(__cplusplus)
+    #define JSON_HEDLEY_NO_RETURN _Pragma("FUNC_NEVER_RETURNS;")
+#elif JSON_HEDLEY_COMPCERT_VERSION_CHECK(3,2,0)
+    #define JSON_HEDLEY_NO_RETURN __attribute((noreturn))
+#elif JSON_HEDLEY_PELLES_VERSION_CHECK(9,0,0)
+    #define JSON_HEDLEY_NO_RETURN __declspec(noreturn)
+#else
+    #define JSON_HEDLEY_NO_RETURN
+#endif
 
-    using object_t = typename BasicJsonType::object_t;
+#if defined(JSON_HEDLEY_NO_ESCAPE)
+    #undef JSON_HEDLEY_NO_ESCAPE
+#endif
+#if JSON_HEDLEY_HAS_ATTRIBUTE(noescape)
+    #define JSON_HEDLEY_NO_ESCAPE __attribute__((__noescape__))
+#else
+    #define JSON_HEDLEY_NO_ESCAPE
+#endif
 
-    // macOS's is_constructible does not play well with nonesuch...
-    static constexpr bool value =
-        std::is_constructible<typename object_t::key_type,
-        typename CompatibleObjectType::key_type>::value and
-        std::is_constructible<typename object_t::mapped_type,
-        typename CompatibleObjectType::mapped_type>::value;
-};
+#if defined(JSON_HEDLEY_UNREACHABLE)
+    #undef JSON_HEDLEY_UNREACHABLE
+#endif
+#if defined(JSON_HEDLEY_UNREACHABLE_RETURN)
+    #undef JSON_HEDLEY_UNREACHABLE_RETURN
+#endif
+#if defined(JSON_HEDLEY_ASSUME)
+    #undef JSON_HEDLEY_ASSUME
+#endif
+#if \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(13,10,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_ASSUME(expr) __assume(expr)
+#elif JSON_HEDLEY_HAS_BUILTIN(__builtin_assume)
+    #define JSON_HEDLEY_ASSUME(expr) __builtin_assume(expr)
+#elif \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,2,0) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(4,0,0)
+    #if defined(__cplusplus)
+        #define JSON_HEDLEY_ASSUME(expr) std::_nassert(expr)
+    #else
+        #define JSON_HEDLEY_ASSUME(expr) _nassert(expr)
+    #endif
+#endif
+#if \
+    (JSON_HEDLEY_HAS_BUILTIN(__builtin_unreachable) && (!defined(JSON_HEDLEY_ARM_VERSION))) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(4,5,0) || \
+    JSON_HEDLEY_PGI_VERSION_CHECK(18,10,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(13,1,5) || \
+    JSON_HEDLEY_CRAY_VERSION_CHECK(10,0,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_UNREACHABLE() __builtin_unreachable()
+#elif defined(JSON_HEDLEY_ASSUME)
+    #define JSON_HEDLEY_UNREACHABLE() JSON_HEDLEY_ASSUME(0)
+#endif
+#if !defined(JSON_HEDLEY_ASSUME)
+    #if defined(JSON_HEDLEY_UNREACHABLE)
+        #define JSON_HEDLEY_ASSUME(expr) JSON_HEDLEY_STATIC_CAST(void, ((expr) ? 1 : (JSON_HEDLEY_UNREACHABLE(), 1)))
+    #else
+        #define JSON_HEDLEY_ASSUME(expr) JSON_HEDLEY_STATIC_CAST(void, expr)
+    #endif
+#endif
+#if defined(JSON_HEDLEY_UNREACHABLE)
+    #if  \
+        JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,2,0) || \
+        JSON_HEDLEY_TI_CL6X_VERSION_CHECK(4,0,0)
+        #define JSON_HEDLEY_UNREACHABLE_RETURN(value) return (JSON_HEDLEY_STATIC_CAST(void, JSON_HEDLEY_ASSUME(0)), (value))
+    #else
+        #define JSON_HEDLEY_UNREACHABLE_RETURN(value) JSON_HEDLEY_UNREACHABLE()
+    #endif
+#else
+    #define JSON_HEDLEY_UNREACHABLE_RETURN(value) return (value)
+#endif
+#if !defined(JSON_HEDLEY_UNREACHABLE)
+    #define JSON_HEDLEY_UNREACHABLE() JSON_HEDLEY_ASSUME(0)
+#endif
 
-template <typename BasicJsonType, typename CompatibleObjectType>
-struct is_compatible_object_type
-    : is_compatible_object_type_impl<BasicJsonType, CompatibleObjectType> {};
+JSON_HEDLEY_DIAGNOSTIC_PUSH
+#if JSON_HEDLEY_HAS_WARNING("-Wpedantic")
+    #pragma clang diagnostic ignored "-Wpedantic"
+#endif
+#if JSON_HEDLEY_HAS_WARNING("-Wc++98-compat-pedantic") && defined(__cplusplus)
+    #pragma clang diagnostic ignored "-Wc++98-compat-pedantic"
+#endif
+#if JSON_HEDLEY_GCC_HAS_WARNING("-Wvariadic-macros",4,0,0)
+    #if defined(__clang__)
+        #pragma clang diagnostic ignored "-Wvariadic-macros"
+    #elif defined(JSON_HEDLEY_GCC_VERSION)
+        #pragma GCC diagnostic ignored "-Wvariadic-macros"
+    #endif
+#endif
+#if defined(JSON_HEDLEY_NON_NULL)
+    #undef JSON_HEDLEY_NON_NULL
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(nonnull) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,3,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0)
+    #define JSON_HEDLEY_NON_NULL(...) __attribute__((__nonnull__(__VA_ARGS__)))
+#else
+    #define JSON_HEDLEY_NON_NULL(...)
+#endif
+JSON_HEDLEY_DIAGNOSTIC_POP
 
-template <typename BasicJsonType, typename ConstructibleObjectType,
-          typename = void>
-struct is_constructible_object_type_impl : std::false_type {};
+#if defined(JSON_HEDLEY_PRINTF_FORMAT)
+    #undef JSON_HEDLEY_PRINTF_FORMAT
+#endif
+#if defined(__MINGW32__) && JSON_HEDLEY_GCC_HAS_ATTRIBUTE(format,4,4,0) && !defined(__USE_MINGW_ANSI_STDIO)
+    #define JSON_HEDLEY_PRINTF_FORMAT(string_idx,first_to_check) __attribute__((__format__(ms_printf, string_idx, first_to_check)))
+#elif defined(__MINGW32__) && JSON_HEDLEY_GCC_HAS_ATTRIBUTE(format,4,4,0) && defined(__USE_MINGW_ANSI_STDIO)
+    #define JSON_HEDLEY_PRINTF_FORMAT(string_idx,first_to_check) __attribute__((__format__(gnu_printf, string_idx, first_to_check)))
+#elif \
+    JSON_HEDLEY_HAS_ATTRIBUTE(format) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,1,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(5,6,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+    (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_PRINTF_FORMAT(string_idx,first_to_check) __attribute__((__format__(__printf__, string_idx, first_to_check)))
+#elif JSON_HEDLEY_PELLES_VERSION_CHECK(6,0,0)
+    #define JSON_HEDLEY_PRINTF_FORMAT(string_idx,first_to_check) __declspec(vaformat(printf,string_idx,first_to_check))
+#else
+    #define JSON_HEDLEY_PRINTF_FORMAT(string_idx,first_to_check)
+#endif
 
-template <typename BasicJsonType, typename ConstructibleObjectType>
-struct is_constructible_object_type_impl <
-    BasicJsonType, ConstructibleObjectType,
-    enable_if_t<is_detected<mapped_type_t, ConstructibleObjectType>::value and
-    is_detected<key_type_t, ConstructibleObjectType>::value >>
-{
-    using object_t = typename BasicJsonType::object_t;
+#if defined(JSON_HEDLEY_CONSTEXPR)
+    #undef JSON_HEDLEY_CONSTEXPR
+#endif
+#if defined(__cplusplus)
+    #if __cplusplus >= 201103L
+        #define JSON_HEDLEY_CONSTEXPR JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_(constexpr)
+    #endif
+#endif
+#if !defined(JSON_HEDLEY_CONSTEXPR)
+    #define JSON_HEDLEY_CONSTEXPR
+#endif
 
-    static constexpr bool value =
-        (std::is_constructible<typename ConstructibleObjectType::key_type, typename object_t::key_type>::value and
-         std::is_same<typename object_t::mapped_type, typename ConstructibleObjectType::mapped_type>::value) or
-        (has_from_json<BasicJsonType, typename ConstructibleObjectType::mapped_type>::value or
-         has_non_default_from_json<BasicJsonType, typename ConstructibleObjectType::mapped_type >::value);
-};
+#if defined(JSON_HEDLEY_PREDICT)
+    #undef JSON_HEDLEY_PREDICT
+#endif
+#if defined(JSON_HEDLEY_LIKELY)
+    #undef JSON_HEDLEY_LIKELY
+#endif
+#if defined(JSON_HEDLEY_UNLIKELY)
+    #undef JSON_HEDLEY_UNLIKELY
+#endif
+#if defined(JSON_HEDLEY_UNPREDICTABLE)
+    #undef JSON_HEDLEY_UNPREDICTABLE
+#endif
+#if JSON_HEDLEY_HAS_BUILTIN(__builtin_unpredictable)
+    #define JSON_HEDLEY_UNPREDICTABLE(expr) __builtin_unpredictable((expr))
+#endif
+#if \
+  (JSON_HEDLEY_HAS_BUILTIN(__builtin_expect_with_probability) && !defined(JSON_HEDLEY_PGI_VERSION)) || \
+  JSON_HEDLEY_GCC_VERSION_CHECK(9,0,0) || \
+  JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+#  define JSON_HEDLEY_PREDICT(expr, value, probability) __builtin_expect_with_probability(  (expr), (value), (probability))
+#  define JSON_HEDLEY_PREDICT_TRUE(expr, probability)   __builtin_expect_with_probability(!!(expr),    1   , (probability))
+#  define JSON_HEDLEY_PREDICT_FALSE(expr, probability)  __builtin_expect_with_probability(!!(expr),    0   , (probability))
+#  define JSON_HEDLEY_LIKELY(expr)                      __builtin_expect                 (!!(expr),    1                  )
+#  define JSON_HEDLEY_UNLIKELY(expr)                    __builtin_expect                 (!!(expr),    0                  )
+#elif \
+  (JSON_HEDLEY_HAS_BUILTIN(__builtin_expect) && !defined(JSON_HEDLEY_INTEL_CL_VERSION)) || \
+  JSON_HEDLEY_GCC_VERSION_CHECK(3,0,0) || \
+  JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+  (JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,15,0) && defined(__cplusplus)) || \
+  JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+  JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) || \
+  JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+  JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,7,0) || \
+  JSON_HEDLEY_TI_CL430_VERSION_CHECK(3,1,0) || \
+  JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,1,0) || \
+  JSON_HEDLEY_TI_CL6X_VERSION_CHECK(6,1,0) || \
+  JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+  JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+  JSON_HEDLEY_TINYC_VERSION_CHECK(0,9,27) || \
+  JSON_HEDLEY_CRAY_VERSION_CHECK(8,1,0) || \
+  JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+#  define JSON_HEDLEY_PREDICT(expr, expected, probability) \
+    (((probability) >= 0.9) ? __builtin_expect((expr), (expected)) : (JSON_HEDLEY_STATIC_CAST(void, expected), (expr)))
+#  define JSON_HEDLEY_PREDICT_TRUE(expr, probability) \
+    (__extension__ ({ \
+        double hedley_probability_ = (probability); \
+        ((hedley_probability_ >= 0.9) ? __builtin_expect(!!(expr), 1) : ((hedley_probability_ <= 0.1) ? __builtin_expect(!!(expr), 0) : !!(expr))); \
+    }))
+#  define JSON_HEDLEY_PREDICT_FALSE(expr, probability) \
+    (__extension__ ({ \
+        double hedley_probability_ = (probability); \
+        ((hedley_probability_ >= 0.9) ? __builtin_expect(!!(expr), 0) : ((hedley_probability_ <= 0.1) ? __builtin_expect(!!(expr), 1) : !!(expr))); \
+    }))
+#  define JSON_HEDLEY_LIKELY(expr)   __builtin_expect(!!(expr), 1)
+#  define JSON_HEDLEY_UNLIKELY(expr) __builtin_expect(!!(expr), 0)
+#else
+#  define JSON_HEDLEY_PREDICT(expr, expected, probability) (JSON_HEDLEY_STATIC_CAST(void, expected), (expr))
+#  define JSON_HEDLEY_PREDICT_TRUE(expr, probability) (!!(expr))
+#  define JSON_HEDLEY_PREDICT_FALSE(expr, probability) (!!(expr))
+#  define JSON_HEDLEY_LIKELY(expr) (!!(expr))
+#  define JSON_HEDLEY_UNLIKELY(expr) (!!(expr))
+#endif
+#if !defined(JSON_HEDLEY_UNPREDICTABLE)
+    #define JSON_HEDLEY_UNPREDICTABLE(expr) JSON_HEDLEY_PREDICT(expr, 1, 0.5)
+#endif
 
-template <typename BasicJsonType, typename ConstructibleObjectType>
-struct is_constructible_object_type
-    : is_constructible_object_type_impl<BasicJsonType,
-      ConstructibleObjectType> {};
+#if defined(JSON_HEDLEY_MALLOC)
+    #undef JSON_HEDLEY_MALLOC
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(malloc) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,1,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,11,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(12,1,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+    (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_MALLOC __attribute__((__malloc__))
+#elif JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,10,0)
+    #define JSON_HEDLEY_MALLOC _Pragma("returns_new_memory")
+#elif \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(14,0,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_MALLOC __declspec(restrict)
+#else
+    #define JSON_HEDLEY_MALLOC
+#endif
 
-template <typename BasicJsonType, typename CompatibleStringType,
-          typename = void>
-struct is_compatible_string_type_impl : std::false_type {};
+#if defined(JSON_HEDLEY_PURE)
+    #undef JSON_HEDLEY_PURE
+#endif
+#if \
+  JSON_HEDLEY_HAS_ATTRIBUTE(pure) || \
+  JSON_HEDLEY_GCC_VERSION_CHECK(2,96,0) || \
+  JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+  JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,11,0) || \
+  JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+  JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) || \
+  JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+  (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+  JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+  (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+  JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+  (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+  JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+  (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+  JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+  JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+  JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+  JSON_HEDLEY_PGI_VERSION_CHECK(17,10,0) || \
+  JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+#  define JSON_HEDLEY_PURE __attribute__((__pure__))
+#elif JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,10,0)
+#  define JSON_HEDLEY_PURE _Pragma("does_not_write_global_data")
+#elif defined(__cplusplus) && \
+    ( \
+      JSON_HEDLEY_TI_CL430_VERSION_CHECK(2,0,1) || \
+      JSON_HEDLEY_TI_CL6X_VERSION_CHECK(4,0,0) || \
+      JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) \
+    )
+#  define JSON_HEDLEY_PURE _Pragma("FUNC_IS_PURE;")
+#else
+#  define JSON_HEDLEY_PURE
+#endif
 
-template <typename BasicJsonType, typename CompatibleStringType>
-struct is_compatible_string_type_impl <
-    BasicJsonType, CompatibleStringType,
-    enable_if_t<is_detected_exact<typename BasicJsonType::string_t::value_type,
-    value_type_t, CompatibleStringType>::value >>
-{
-    static constexpr auto value =
-        std::is_constructible<typename BasicJsonType::string_t, CompatibleStringType>::value;
-};
+#if defined(JSON_HEDLEY_CONST)
+    #undef JSON_HEDLEY_CONST
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(const) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(2,5,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,11,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+    (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    JSON_HEDLEY_PGI_VERSION_CHECK(17,10,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_CONST __attribute__((__const__))
+#elif \
+    JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,10,0)
+    #define JSON_HEDLEY_CONST _Pragma("no_side_effect")
+#else
+    #define JSON_HEDLEY_CONST JSON_HEDLEY_PURE
+#endif
 
-template <typename BasicJsonType, typename ConstructibleStringType>
-struct is_compatible_string_type
-    : is_compatible_string_type_impl<BasicJsonType, ConstructibleStringType> {};
+#if defined(JSON_HEDLEY_RESTRICT)
+    #undef JSON_HEDLEY_RESTRICT
+#endif
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) && !defined(__cplusplus)
+    #define JSON_HEDLEY_RESTRICT restrict
+#elif \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,1,0) || \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(14,0,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) || \
+    JSON_HEDLEY_PGI_VERSION_CHECK(17,10,0) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,2,4) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(8,1,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    (JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,14,0) && defined(__cplusplus)) || \
+    JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0) || \
+    defined(__clang__) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_RESTRICT __restrict
+#elif JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,3,0) && !defined(__cplusplus)
+    #define JSON_HEDLEY_RESTRICT _Restrict
+#else
+    #define JSON_HEDLEY_RESTRICT
+#endif
 
-template <typename BasicJsonType, typename ConstructibleStringType,
-          typename = void>
-struct is_constructible_string_type_impl : std::false_type {};
+#if defined(JSON_HEDLEY_INLINE)
+    #undef JSON_HEDLEY_INLINE
+#endif
+#if \
+    (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || \
+    (defined(__cplusplus) && (__cplusplus >= 199711L))
+    #define JSON_HEDLEY_INLINE inline
+#elif \
+    defined(JSON_HEDLEY_GCC_VERSION) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(6,2,0)
+    #define JSON_HEDLEY_INLINE __inline__
+#elif \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(12,0,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,1,0) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(3,1,0) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,2,0) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(8,0,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_INLINE __inline
+#else
+    #define JSON_HEDLEY_INLINE
+#endif
 
-template <typename BasicJsonType, typename ConstructibleStringType>
-struct is_constructible_string_type_impl <
-    BasicJsonType, ConstructibleStringType,
-    enable_if_t<is_detected_exact<typename BasicJsonType::string_t::value_type,
-    value_type_t, ConstructibleStringType>::value >>
-{
-    static constexpr auto value =
-        std::is_constructible<ConstructibleStringType,
-        typename BasicJsonType::string_t>::value;
-};
+#if defined(JSON_HEDLEY_ALWAYS_INLINE)
+    #undef JSON_HEDLEY_ALWAYS_INLINE
+#endif
+#if \
+  JSON_HEDLEY_HAS_ATTRIBUTE(always_inline) || \
+  JSON_HEDLEY_GCC_VERSION_CHECK(4,0,0) || \
+  JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+  JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,11,0) || \
+  JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+  JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) || \
+  JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+  (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+  JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+  (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+  JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+  (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+  JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+  (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+  JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+  JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+  JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+  JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10) || \
+  JSON_HEDLEY_IAR_VERSION_CHECK(8,10,0)
+#  define JSON_HEDLEY_ALWAYS_INLINE __attribute__((__always_inline__)) JSON_HEDLEY_INLINE
+#elif \
+  JSON_HEDLEY_MSVC_VERSION_CHECK(12,0,0) || \
+  JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+#  define JSON_HEDLEY_ALWAYS_INLINE __forceinline
+#elif defined(__cplusplus) && \
+    ( \
+      JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+      JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+      JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+      JSON_HEDLEY_TI_CL6X_VERSION_CHECK(6,1,0) || \
+      JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+      JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) \
+    )
+#  define JSON_HEDLEY_ALWAYS_INLINE _Pragma("FUNC_ALWAYS_INLINE;")
+#elif JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0)
+#  define JSON_HEDLEY_ALWAYS_INLINE _Pragma("inline=forced")
+#else
+#  define JSON_HEDLEY_ALWAYS_INLINE JSON_HEDLEY_INLINE
+#endif
 
-template <typename BasicJsonType, typename ConstructibleStringType>
-struct is_constructible_string_type
-    : is_constructible_string_type_impl<BasicJsonType, ConstructibleStringType> {};
+#if defined(JSON_HEDLEY_NEVER_INLINE)
+    #undef JSON_HEDLEY_NEVER_INLINE
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(noinline) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(4,0,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,11,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(10,1,0) || \
+    JSON_HEDLEY_TI_VERSION_CHECK(15,12,0) || \
+    (JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(4,8,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_ARMCL_VERSION_CHECK(5,2,0) || \
+    (JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL2000_VERSION_CHECK(6,4,0) || \
+    (JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,0,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL430_VERSION_CHECK(4,3,0) || \
+    (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) || \
+    JSON_HEDLEY_TI_CL7X_VERSION_CHECK(1,2,0) || \
+    JSON_HEDLEY_TI_CLPRU_VERSION_CHECK(2,1,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10) || \
+    JSON_HEDLEY_IAR_VERSION_CHECK(8,10,0)
+    #define JSON_HEDLEY_NEVER_INLINE __attribute__((__noinline__))
+#elif \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(13,10,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_NEVER_INLINE __declspec(noinline)
+#elif JSON_HEDLEY_PGI_VERSION_CHECK(10,2,0)
+    #define JSON_HEDLEY_NEVER_INLINE _Pragma("noinline")
+#elif JSON_HEDLEY_TI_CL6X_VERSION_CHECK(6,0,0) && defined(__cplusplus)
+    #define JSON_HEDLEY_NEVER_INLINE _Pragma("FUNC_CANNOT_INLINE;")
+#elif JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0)
+    #define JSON_HEDLEY_NEVER_INLINE _Pragma("inline=never")
+#elif JSON_HEDLEY_COMPCERT_VERSION_CHECK(3,2,0)
+    #define JSON_HEDLEY_NEVER_INLINE __attribute((noinline))
+#elif JSON_HEDLEY_PELLES_VERSION_CHECK(9,0,0)
+    #define JSON_HEDLEY_NEVER_INLINE __declspec(noinline)
+#else
+    #define JSON_HEDLEY_NEVER_INLINE
+#endif
 
-template <typename BasicJsonType, typename CompatibleArrayType, typename = void>
-struct is_compatible_array_type_impl : std::false_type {};
+#if defined(JSON_HEDLEY_PRIVATE)
+    #undef JSON_HEDLEY_PRIVATE
+#endif
+#if defined(JSON_HEDLEY_PUBLIC)
+    #undef JSON_HEDLEY_PUBLIC
+#endif
+#if defined(JSON_HEDLEY_IMPORT)
+    #undef JSON_HEDLEY_IMPORT
+#endif
+#if defined(_WIN32) || defined(__CYGWIN__)
+#  define JSON_HEDLEY_PRIVATE
+#  define JSON_HEDLEY_PUBLIC   __declspec(dllexport)
+#  define JSON_HEDLEY_IMPORT   __declspec(dllimport)
+#else
+#  if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(visibility) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,3,0) || \
+    JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,11,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(13,1,0) || \
+    ( \
+      defined(__TI_EABI__) && \
+      ( \
+        (JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,2,0) && defined(__TI_GNU_ATTRIBUTE_SUPPORT__)) || \
+        JSON_HEDLEY_TI_CL6X_VERSION_CHECK(7,5,0) \
+      ) \
+    ) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+#    define JSON_HEDLEY_PRIVATE __attribute__((__visibility__("hidden")))
+#    define JSON_HEDLEY_PUBLIC  __attribute__((__visibility__("default")))
+#  else
+#    define JSON_HEDLEY_PRIVATE
+#    define JSON_HEDLEY_PUBLIC
+#  endif
+#  define JSON_HEDLEY_IMPORT    extern
+#endif
 
-template <typename BasicJsonType, typename CompatibleArrayType>
-struct is_compatible_array_type_impl <
-    BasicJsonType, CompatibleArrayType,
-    enable_if_t<is_detected<value_type_t, CompatibleArrayType>::value and
-    is_detected<iterator_t, CompatibleArrayType>::value and
-// This is needed because json_reverse_iterator has a ::iterator type...
-// Therefore it is detected as a CompatibleArrayType.
-// The real fix would be to have an Iterable concept.
-    not is_iterator_traits<
-    iterator_traits<CompatibleArrayType>>::value >>
-{
-    static constexpr bool value =
-        std::is_constructible<BasicJsonType,
-        typename CompatibleArrayType::value_type>::value;
-};
+#if defined(JSON_HEDLEY_NO_THROW)
+    #undef JSON_HEDLEY_NO_THROW
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(nothrow) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,3,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_NO_THROW __attribute__((__nothrow__))
+#elif \
+    JSON_HEDLEY_MSVC_VERSION_CHECK(13,1,0) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0)
+    #define JSON_HEDLEY_NO_THROW __declspec(nothrow)
+#else
+    #define JSON_HEDLEY_NO_THROW
+#endif
 
-template <typename BasicJsonType, typename CompatibleArrayType>
-struct is_compatible_array_type
-    : is_compatible_array_type_impl<BasicJsonType, CompatibleArrayType> {};
+#if defined(JSON_HEDLEY_FALL_THROUGH)
+    #undef JSON_HEDLEY_FALL_THROUGH
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(fallthrough) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(7,0,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_FALL_THROUGH __attribute__((__fallthrough__))
+#elif JSON_HEDLEY_HAS_CPP_ATTRIBUTE_NS(clang,fallthrough)
+    #define JSON_HEDLEY_FALL_THROUGH JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[clang::fallthrough]])
+#elif JSON_HEDLEY_HAS_CPP_ATTRIBUTE(fallthrough)
+    #define JSON_HEDLEY_FALL_THROUGH JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[fallthrough]])
+#elif defined(__fallthrough) /* SAL */
+    #define JSON_HEDLEY_FALL_THROUGH __fallthrough
+#else
+    #define JSON_HEDLEY_FALL_THROUGH
+#endif
 
-template <typename BasicJsonType, typename ConstructibleArrayType, typename = void>
-struct is_constructible_array_type_impl : std::false_type {};
+#if defined(JSON_HEDLEY_RETURNS_NON_NULL)
+    #undef JSON_HEDLEY_RETURNS_NON_NULL
+#endif
+#if \
+    JSON_HEDLEY_HAS_ATTRIBUTE(returns_nonnull) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_RETURNS_NON_NULL __attribute__((__returns_nonnull__))
+#elif defined(_Ret_notnull_) /* SAL */
+    #define JSON_HEDLEY_RETURNS_NON_NULL _Ret_notnull_
+#else
+    #define JSON_HEDLEY_RETURNS_NON_NULL
+#endif
 
-template <typename BasicJsonType, typename ConstructibleArrayType>
-struct is_constructible_array_type_impl <
-    BasicJsonType, ConstructibleArrayType,
-    enable_if_t<std::is_same<ConstructibleArrayType,
-    typename BasicJsonType::value_type>::value >>
-            : std::true_type {};
+#if defined(JSON_HEDLEY_ARRAY_PARAM)
+    #undef JSON_HEDLEY_ARRAY_PARAM
+#endif
+#if \
+    defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) && \
+    !defined(__STDC_NO_VLA__) && \
+    !defined(__cplusplus) && \
+    !defined(JSON_HEDLEY_PGI_VERSION) && \
+    !defined(JSON_HEDLEY_TINYC_VERSION)
+    #define JSON_HEDLEY_ARRAY_PARAM(name) (name)
+#else
+    #define JSON_HEDLEY_ARRAY_PARAM(name)
+#endif
 
-template <typename BasicJsonType, typename ConstructibleArrayType>
-struct is_constructible_array_type_impl <
-    BasicJsonType, ConstructibleArrayType,
-    enable_if_t<not std::is_same<ConstructibleArrayType,
-    typename BasicJsonType::value_type>::value and
-    is_detected<value_type_t, ConstructibleArrayType>::value and
-    is_detected<iterator_t, ConstructibleArrayType>::value and
-    is_complete_type<
-    detected_t<value_type_t, ConstructibleArrayType>>::value >>
-{
-    static constexpr bool value =
-        // This is needed because json_reverse_iterator has a ::iterator type,
-        // furthermore, std::back_insert_iterator (and other iterators) have a base class `iterator`...
-        // Therefore it is detected as a ConstructibleArrayType.
-        // The real fix would be to have an Iterable concept.
-        not is_iterator_traits <
-        iterator_traits<ConstructibleArrayType >>::value and
-
-        (std::is_same<typename ConstructibleArrayType::value_type, typename BasicJsonType::array_t::value_type>::value or
-         has_from_json<BasicJsonType,
-         typename ConstructibleArrayType::value_type>::value or
-         has_non_default_from_json <
-         BasicJsonType, typename ConstructibleArrayType::value_type >::value);
-};
+#if defined(JSON_HEDLEY_IS_CONSTANT)
+    #undef JSON_HEDLEY_IS_CONSTANT
+#endif
+#if defined(JSON_HEDLEY_REQUIRE_CONSTEXPR)
+    #undef JSON_HEDLEY_REQUIRE_CONSTEXPR
+#endif
+/* JSON_HEDLEY_IS_CONSTEXPR_ is for
+   HEDLEY INTERNAL USE ONLY.  API subject to change without notice. */
+#if defined(JSON_HEDLEY_IS_CONSTEXPR_)
+    #undef JSON_HEDLEY_IS_CONSTEXPR_
+#endif
+#if \
+    JSON_HEDLEY_HAS_BUILTIN(__builtin_constant_p) || \
+    JSON_HEDLEY_GCC_VERSION_CHECK(3,4,0) || \
+    JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+    JSON_HEDLEY_TINYC_VERSION_CHECK(0,9,19) || \
+    JSON_HEDLEY_ARM_VERSION_CHECK(4,1,0) || \
+    JSON_HEDLEY_IBM_VERSION_CHECK(13,1,0) || \
+    JSON_HEDLEY_TI_CL6X_VERSION_CHECK(6,1,0) || \
+    (JSON_HEDLEY_SUNPRO_VERSION_CHECK(5,10,0) && !defined(__cplusplus)) || \
+    JSON_HEDLEY_CRAY_VERSION_CHECK(8,1,0) || \
+    JSON_HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
+    #define JSON_HEDLEY_IS_CONSTANT(expr) __builtin_constant_p(expr)
+#endif
+#if !defined(__cplusplus)
+#  if \
+       JSON_HEDLEY_HAS_BUILTIN(__builtin_types_compatible_p) || \
+       JSON_HEDLEY_GCC_VERSION_CHECK(3,4,0) || \
+       JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+       JSON_HEDLEY_IBM_VERSION_CHECK(13,1,0) || \
+       JSON_HEDLEY_CRAY_VERSION_CHECK(8,1,0) || \
+       JSON_HEDLEY_ARM_VERSION_CHECK(5,4,0) || \
+       JSON_HEDLEY_TINYC_VERSION_CHECK(0,9,24)
+#if defined(__INTPTR_TYPE__)
+    #define JSON_HEDLEY_IS_CONSTEXPR_(expr) __builtin_types_compatible_p(__typeof__((1 ? (void*) ((__INTPTR_TYPE__) ((expr) * 0)) : (int*) 0)), int*)
+#else
+    #include <stdint.h>
+    #define JSON_HEDLEY_IS_CONSTEXPR_(expr) __builtin_types_compatible_p(__typeof__((1 ? (void*) ((intptr_t) ((expr) * 0)) : (int*) 0)), int*)
+#endif
+#  elif \
+       ( \
+          defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) && \
+          !defined(JSON_HEDLEY_SUNPRO_VERSION) && \
+          !defined(JSON_HEDLEY_PGI_VERSION) && \
+          !defined(JSON_HEDLEY_IAR_VERSION)) || \
+       (JSON_HEDLEY_HAS_EXTENSION(c_generic_selections) && !defined(JSON_HEDLEY_IAR_VERSION)) || \
+       JSON_HEDLEY_GCC_VERSION_CHECK(4,9,0) || \
+       JSON_HEDLEY_INTEL_VERSION_CHECK(17,0,0) || \
+       JSON_HEDLEY_IBM_VERSION_CHECK(12,1,0) || \
+       JSON_HEDLEY_ARM_VERSION_CHECK(5,3,0)
+#if defined(__INTPTR_TYPE__)
+    #define JSON_HEDLEY_IS_CONSTEXPR_(expr) _Generic((1 ? (void*) ((__INTPTR_TYPE__) ((expr) * 0)) : (int*) 0), int*: 1, void*: 0)
+#else
+    #include <stdint.h>
+    #define JSON_HEDLEY_IS_CONSTEXPR_(expr) _Generic((1 ? (void*) ((intptr_t) * 0) : (int*) 0), int*: 1, void*: 0)
+#endif
+#  elif \
+       defined(JSON_HEDLEY_GCC_VERSION) || \
+       defined(JSON_HEDLEY_INTEL_VERSION) || \
+       defined(JSON_HEDLEY_TINYC_VERSION) || \
+       defined(JSON_HEDLEY_TI_ARMCL_VERSION) || \
+       JSON_HEDLEY_TI_CL430_VERSION_CHECK(18,12,0) || \
+       defined(JSON_HEDLEY_TI_CL2000_VERSION) || \
+       defined(JSON_HEDLEY_TI_CL6X_VERSION) || \
+       defined(JSON_HEDLEY_TI_CL7X_VERSION) || \
+       defined(JSON_HEDLEY_TI_CLPRU_VERSION) || \
+       defined(__clang__)
+#    define JSON_HEDLEY_IS_CONSTEXPR_(expr) ( \
+        sizeof(void) != \
+        sizeof(*( \
+                  1 ? \
+                  ((void*) ((expr) * 0L) ) : \
+((struct { char v[sizeof(void) * 2]; } *) 1) \
+                ) \
+              ) \
+                                            )
+#  endif
+#endif
+#if defined(JSON_HEDLEY_IS_CONSTEXPR_)
+    #if !defined(JSON_HEDLEY_IS_CONSTANT)
+        #define JSON_HEDLEY_IS_CONSTANT(expr) JSON_HEDLEY_IS_CONSTEXPR_(expr)
+    #endif
+    #define JSON_HEDLEY_REQUIRE_CONSTEXPR(expr) (JSON_HEDLEY_IS_CONSTEXPR_(expr) ? (expr) : (-1))
+#else
+    #if !defined(JSON_HEDLEY_IS_CONSTANT)
+        #define JSON_HEDLEY_IS_CONSTANT(expr) (0)
+    #endif
+    #define JSON_HEDLEY_REQUIRE_CONSTEXPR(expr) (expr)
+#endif
 
-template <typename BasicJsonType, typename ConstructibleArrayType>
-struct is_constructible_array_type
-    : is_constructible_array_type_impl<BasicJsonType, ConstructibleArrayType> {};
+#if defined(JSON_HEDLEY_BEGIN_C_DECLS)
+    #undef JSON_HEDLEY_BEGIN_C_DECLS
+#endif
+#if defined(JSON_HEDLEY_END_C_DECLS)
+    #undef JSON_HEDLEY_END_C_DECLS
+#endif
+#if defined(JSON_HEDLEY_C_DECL)
+    #undef JSON_HEDLEY_C_DECL
+#endif
+#if defined(__cplusplus)
+    #define JSON_HEDLEY_BEGIN_C_DECLS extern "C" {
+    #define JSON_HEDLEY_END_C_DECLS }
+    #define JSON_HEDLEY_C_DECL extern "C"
+#else
+    #define JSON_HEDLEY_BEGIN_C_DECLS
+    #define JSON_HEDLEY_END_C_DECLS
+    #define JSON_HEDLEY_C_DECL
+#endif
 
-template <typename RealIntegerType, typename CompatibleNumberIntegerType,
-          typename = void>
-struct is_compatible_integer_type_impl : std::false_type {};
+#if defined(JSON_HEDLEY_STATIC_ASSERT)
+    #undef JSON_HEDLEY_STATIC_ASSERT
+#endif
+#if \
+  !defined(__cplusplus) && ( \
+      (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)) || \
+      (JSON_HEDLEY_HAS_FEATURE(c_static_assert) && !defined(JSON_HEDLEY_INTEL_CL_VERSION)) || \
+      JSON_HEDLEY_GCC_VERSION_CHECK(6,0,0) || \
+      JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0) || \
+      defined(_Static_assert) \
+    )
+#  define JSON_HEDLEY_STATIC_ASSERT(expr, message) _Static_assert(expr, message)
+#elif \
+  (defined(__cplusplus) && (__cplusplus >= 201103L)) || \
+  JSON_HEDLEY_MSVC_VERSION_CHECK(16,0,0) || \
+  JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+#  define JSON_HEDLEY_STATIC_ASSERT(expr, message) JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_(static_assert(expr, message))
+#else
+#  define JSON_HEDLEY_STATIC_ASSERT(expr, message)
+#endif
 
-template <typename RealIntegerType, typename CompatibleNumberIntegerType>
-struct is_compatible_integer_type_impl <
-    RealIntegerType, CompatibleNumberIntegerType,
-    enable_if_t<std::is_integral<RealIntegerType>::value and
-    std::is_integral<CompatibleNumberIntegerType>::value and
-    not std::is_same<bool, CompatibleNumberIntegerType>::value >>
-{
-    // is there an assert somewhere on overflows?
-    using RealLimits = std::numeric_limits<RealIntegerType>;
-    using CompatibleLimits = std::numeric_limits<CompatibleNumberIntegerType>;
+#if defined(JSON_HEDLEY_NULL)
+    #undef JSON_HEDLEY_NULL
+#endif
+#if defined(__cplusplus)
+    #if __cplusplus >= 201103L
+        #define JSON_HEDLEY_NULL JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_(nullptr)
+    #elif defined(NULL)
+        #define JSON_HEDLEY_NULL NULL
+    #else
+        #define JSON_HEDLEY_NULL JSON_HEDLEY_STATIC_CAST(void*, 0)
+    #endif
+#elif defined(NULL)
+    #define JSON_HEDLEY_NULL NULL
+#else
+    #define JSON_HEDLEY_NULL ((void*) 0)
+#endif
 
-    static constexpr auto value =
-        std::is_constructible<RealIntegerType,
-        CompatibleNumberIntegerType>::value and
-        CompatibleLimits::is_integer and
-        RealLimits::is_signed == CompatibleLimits::is_signed;
-};
+#if defined(JSON_HEDLEY_MESSAGE)
+    #undef JSON_HEDLEY_MESSAGE
+#endif
+#if JSON_HEDLEY_HAS_WARNING("-Wunknown-pragmas")
+#  define JSON_HEDLEY_MESSAGE(msg) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS \
+    JSON_HEDLEY_PRAGMA(message msg) \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#elif \
+  JSON_HEDLEY_GCC_VERSION_CHECK(4,4,0) || \
+  JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0)
+#  define JSON_HEDLEY_MESSAGE(msg) JSON_HEDLEY_PRAGMA(message msg)
+#elif JSON_HEDLEY_CRAY_VERSION_CHECK(5,0,0)
+#  define JSON_HEDLEY_MESSAGE(msg) JSON_HEDLEY_PRAGMA(_CRI message msg)
+#elif JSON_HEDLEY_IAR_VERSION_CHECK(8,0,0)
+#  define JSON_HEDLEY_MESSAGE(msg) JSON_HEDLEY_PRAGMA(message(msg))
+#elif JSON_HEDLEY_PELLES_VERSION_CHECK(2,0,0)
+#  define JSON_HEDLEY_MESSAGE(msg) JSON_HEDLEY_PRAGMA(message(msg))
+#else
+#  define JSON_HEDLEY_MESSAGE(msg)
+#endif
 
-template <typename RealIntegerType, typename CompatibleNumberIntegerType>
-struct is_compatible_integer_type
-    : is_compatible_integer_type_impl<RealIntegerType,
-      CompatibleNumberIntegerType> {};
+#if defined(JSON_HEDLEY_WARNING)
+    #undef JSON_HEDLEY_WARNING
+#endif
+#if JSON_HEDLEY_HAS_WARNING("-Wunknown-pragmas")
+#  define JSON_HEDLEY_WARNING(msg) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS \
+    JSON_HEDLEY_PRAGMA(clang warning msg) \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#elif \
+  JSON_HEDLEY_GCC_VERSION_CHECK(4,8,0) || \
+  JSON_HEDLEY_PGI_VERSION_CHECK(18,4,0) || \
+  JSON_HEDLEY_INTEL_VERSION_CHECK(13,0,0)
+#  define JSON_HEDLEY_WARNING(msg) JSON_HEDLEY_PRAGMA(GCC warning msg)
+#elif \
+  JSON_HEDLEY_MSVC_VERSION_CHECK(15,0,0) || \
+  JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+#  define JSON_HEDLEY_WARNING(msg) JSON_HEDLEY_PRAGMA(message(msg))
+#else
+#  define JSON_HEDLEY_WARNING(msg) JSON_HEDLEY_MESSAGE(msg)
+#endif
 
-template <typename BasicJsonType, typename CompatibleType, typename = void>
-struct is_compatible_type_impl: std::false_type {};
+#if defined(JSON_HEDLEY_REQUIRE)
+    #undef JSON_HEDLEY_REQUIRE
+#endif
+#if defined(JSON_HEDLEY_REQUIRE_MSG)
+    #undef JSON_HEDLEY_REQUIRE_MSG
+#endif
+#if JSON_HEDLEY_HAS_ATTRIBUTE(diagnose_if)
+#  if JSON_HEDLEY_HAS_WARNING("-Wgcc-compat")
+#    define JSON_HEDLEY_REQUIRE(expr) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    _Pragma("clang diagnostic ignored \"-Wgcc-compat\"") \
+    __attribute__((diagnose_if(!(expr), #expr, "error"))) \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#    define JSON_HEDLEY_REQUIRE_MSG(expr,msg) \
+    JSON_HEDLEY_DIAGNOSTIC_PUSH \
+    _Pragma("clang diagnostic ignored \"-Wgcc-compat\"") \
+    __attribute__((diagnose_if(!(expr), msg, "error"))) \
+    JSON_HEDLEY_DIAGNOSTIC_POP
+#  else
+#    define JSON_HEDLEY_REQUIRE(expr) __attribute__((diagnose_if(!(expr), #expr, "error")))
+#    define JSON_HEDLEY_REQUIRE_MSG(expr,msg) __attribute__((diagnose_if(!(expr), msg, "error")))
+#  endif
+#else
+#  define JSON_HEDLEY_REQUIRE(expr)
+#  define JSON_HEDLEY_REQUIRE_MSG(expr,msg)
+#endif
 
-template <typename BasicJsonType, typename CompatibleType>
-struct is_compatible_type_impl <
-    BasicJsonType, CompatibleType,
-    enable_if_t<is_complete_type<CompatibleType>::value >>
-{
-    static constexpr bool value =
-        has_to_json<BasicJsonType, CompatibleType>::value;
-};
+#if defined(JSON_HEDLEY_FLAGS)
+    #undef JSON_HEDLEY_FLAGS
+#endif
+#if JSON_HEDLEY_HAS_ATTRIBUTE(flag_enum) && (!defined(__cplusplus) || JSON_HEDLEY_HAS_WARNING("-Wbitfield-enum-conversion"))
+    #define JSON_HEDLEY_FLAGS __attribute__((__flag_enum__))
+#else
+    #define JSON_HEDLEY_FLAGS
+#endif
 
-template <typename BasicJsonType, typename CompatibleType>
-struct is_compatible_type
-    : is_compatible_type_impl<BasicJsonType, CompatibleType> {};
-}  // namespace detail
-}  // namespace nlohmann
+#if defined(JSON_HEDLEY_FLAGS_CAST)
+    #undef JSON_HEDLEY_FLAGS_CAST
+#endif
+#if JSON_HEDLEY_INTEL_VERSION_CHECK(19,0,0)
+#  define JSON_HEDLEY_FLAGS_CAST(T, expr) (__extension__ ({ \
+        JSON_HEDLEY_DIAGNOSTIC_PUSH \
+        _Pragma("warning(disable:188)") \
+        ((T) (expr)); \
+        JSON_HEDLEY_DIAGNOSTIC_POP \
+    }))
+#else
+#  define JSON_HEDLEY_FLAGS_CAST(T, expr) JSON_HEDLEY_STATIC_CAST(T, expr)
+#endif
 
-// #include <nlohmann/detail/exceptions.hpp>
+#if defined(JSON_HEDLEY_EMPTY_BASES)
+    #undef JSON_HEDLEY_EMPTY_BASES
+#endif
+#if \
+    (JSON_HEDLEY_MSVC_VERSION_CHECK(19,0,23918) && !JSON_HEDLEY_MSVC_VERSION_CHECK(20,0,0)) || \
+    JSON_HEDLEY_INTEL_CL_VERSION_CHECK(2021,1,0)
+    #define JSON_HEDLEY_EMPTY_BASES __declspec(empty_bases)
+#else
+    #define JSON_HEDLEY_EMPTY_BASES
+#endif
 
+/* Remaining macros are deprecated. */
 
-#include <exception> // exception
-#include <stdexcept> // runtime_error
-#include <string> // to_string
+#if defined(JSON_HEDLEY_GCC_NOT_CLANG_VERSION_CHECK)
+    #undef JSON_HEDLEY_GCC_NOT_CLANG_VERSION_CHECK
+#endif
+#if defined(__clang__)
+    #define JSON_HEDLEY_GCC_NOT_CLANG_VERSION_CHECK(major,minor,patch) (0)
+#else
+    #define JSON_HEDLEY_GCC_NOT_CLANG_VERSION_CHECK(major,minor,patch) JSON_HEDLEY_GCC_VERSION_CHECK(major,minor,patch)
+#endif
 
-// #include <nlohmann/detail/input/position_t.hpp>
+#if defined(JSON_HEDLEY_CLANG_HAS_ATTRIBUTE)
+    #undef JSON_HEDLEY_CLANG_HAS_ATTRIBUTE
+#endif
+#define JSON_HEDLEY_CLANG_HAS_ATTRIBUTE(attribute) JSON_HEDLEY_HAS_ATTRIBUTE(attribute)
 
+#if defined(JSON_HEDLEY_CLANG_HAS_CPP_ATTRIBUTE)
+    #undef JSON_HEDLEY_CLANG_HAS_CPP_ATTRIBUTE
+#endif
+#define JSON_HEDLEY_CLANG_HAS_CPP_ATTRIBUTE(attribute) JSON_HEDLEY_HAS_CPP_ATTRIBUTE(attribute)
+
+#if defined(JSON_HEDLEY_CLANG_HAS_BUILTIN)
+    #undef JSON_HEDLEY_CLANG_HAS_BUILTIN
+#endif
+#define JSON_HEDLEY_CLANG_HAS_BUILTIN(builtin) JSON_HEDLEY_HAS_BUILTIN(builtin)
+
+#if defined(JSON_HEDLEY_CLANG_HAS_FEATURE)
+    #undef JSON_HEDLEY_CLANG_HAS_FEATURE
+#endif
+#define JSON_HEDLEY_CLANG_HAS_FEATURE(feature) JSON_HEDLEY_HAS_FEATURE(feature)
+
+#if defined(JSON_HEDLEY_CLANG_HAS_EXTENSION)
+    #undef JSON_HEDLEY_CLANG_HAS_EXTENSION
+#endif
+#define JSON_HEDLEY_CLANG_HAS_EXTENSION(extension) JSON_HEDLEY_HAS_EXTENSION(extension)
+
+#if defined(JSON_HEDLEY_CLANG_HAS_DECLSPEC_DECLSPEC_ATTRIBUTE)
+    #undef JSON_HEDLEY_CLANG_HAS_DECLSPEC_DECLSPEC_ATTRIBUTE
+#endif
+#define JSON_HEDLEY_CLANG_HAS_DECLSPEC_ATTRIBUTE(attribute) JSON_HEDLEY_HAS_DECLSPEC_ATTRIBUTE(attribute)
+
+#if defined(JSON_HEDLEY_CLANG_HAS_WARNING)
+    #undef JSON_HEDLEY_CLANG_HAS_WARNING
+#endif
+#define JSON_HEDLEY_CLANG_HAS_WARNING(warning) JSON_HEDLEY_HAS_WARNING(warning)
+
+#endif /* !defined(JSON_HEDLEY_VERSION) || (JSON_HEDLEY_VERSION < X) */
+
+// #include <nlohmann/detail/meta/detected.hpp>
+
+
+#include <type_traits>
+
+// #include <nlohmann/detail/meta/void_t.hpp>
 
-#include <cstddef> // size_t
 
 namespace nlohmann
 {
 namespace detail
 {
-/// struct to capture the start position of the current token
-struct position_t
+template<typename ...Ts> struct make_void
 {
-    /// the total number of characters read
-    std::size_t chars_read_total = 0;
-    /// the number of characters read in the current line
-    std::size_t chars_read_current_line = 0;
-    /// the number of lines read
-    std::size_t lines_read = 0;
-
-    /// conversion to size_t to preserve SAX interface
-    constexpr operator size_t() const
-    {
-        return chars_read_total;
-    }
+    using type = void;
 };
-
-}
-}
+template<typename ...Ts> using void_t = typename make_void<Ts...>::type;
+} // namespace detail
+}  // namespace nlohmann
 
 
+// https://en.cppreference.com/w/cpp/experimental/is_detected
 namespace nlohmann
 {
 namespace detail
 {
-////////////////
-// exceptions //
-////////////////
-
-/*!
-@brief general exception of the @ref basic_json class
+struct nonesuch
+{
+    nonesuch() = delete;
+    ~nonesuch() = delete;
+    nonesuch(nonesuch const&) = delete;
+    nonesuch(nonesuch const&&) = delete;
+    void operator=(nonesuch const&) = delete;
+    void operator=(nonesuch&&) = delete;
+};
 
-This class is an extension of `std::exception` objects with a member @a id for
-exception ids. It is used as the base class for all exceptions thrown by the
-@ref basic_json class. This class can hence be used as "wildcard" to catch
-exceptions.
+template<class Default,
+         class AlwaysVoid,
+         template<class...> class Op,
+         class... Args>
+struct detector
+{
+    using value_t = std::false_type;
+    using type = Default;
+};
 
-Subclasses:
-- @ref parse_error for exceptions indicating a parse error
-- @ref invalid_iterator for exceptions indicating errors with iterators
-- @ref type_error for exceptions indicating executing a member function with
-                  a wrong type
-- @ref out_of_range for exceptions indicating access out of the defined range
-- @ref other_error for exceptions indicating other library errors
+template<class Default, template<class...> class Op, class... Args>
+struct detector<Default, void_t<Op<Args...>>, Op, Args...>
+{
+    using value_t = std::true_type;
+    using type = Op<Args...>;
+};
 
-@internal
-@note To have nothrow-copy-constructible exceptions, we internally use
-      `std::runtime_error` which can cope with arbitrary-length error messages.
-      Intermediate strings are built with static functions and then passed to
-      the actual constructor.
-@endinternal
+template<template<class...> class Op, class... Args>
+using is_detected = typename detector<nonesuch, void, Op, Args...>::value_t;
 
-@liveexample{The following code shows how arbitrary library exceptions can be
-caught.,exception}
+template<template<class...> class Op, class... Args>
+struct is_detected_lazy : is_detected<Op, Args...> { };
 
-@since version 3.0.0
-*/
-class exception : public std::exception
-{
-  public:
-    /// returns the explanatory string
-    const char* what() const noexcept override
-    {
-        return m.what();
-    }
+template<template<class...> class Op, class... Args>
+using detected_t = typename detector<nonesuch, void, Op, Args...>::type;
 
-    /// the id of the exception
-    const int id;
+template<class Default, template<class...> class Op, class... Args>
+using detected_or = detector<Default, void, Op, Args...>;
 
-  protected:
-    exception(int id_, const char* what_arg) : id(id_), m(what_arg) {}
+template<class Default, template<class...> class Op, class... Args>
+using detected_or_t = typename detected_or<Default, Op, Args...>::type;
 
-    static std::string name(const std::string& ename, int id_)
-    {
-        return "[json.exception." + ename + "." + std::to_string(id_) + "] ";
-    }
+template<class Expected, template<class...> class Op, class... Args>
+using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;
 
-  private:
-    /// an exception object as storage for error messages
-    std::runtime_error m;
-};
+template<class To, template<class...> class Op, class... Args>
+using is_detected_convertible =
+    std::is_convertible<detected_t<Op, Args...>, To>;
+}  // namespace detail
+}  // namespace nlohmann
 
-/*!
-@brief exception indicating a parse error
 
-This exception is thrown by the library when a parse error occurs. Parse errors
-can occur during the deserialization of JSON text, CBOR, MessagePack, as well
-as when using JSON Patch.
+// This file contains all internal macro definitions
+// You MUST include macro_unscope.hpp at the end of json.hpp to undef all of them
 
-Member @a byte holds the byte index of the last read character in the input
-file.
+// exclude unsupported compilers
+#if !defined(JSON_SKIP_UNSUPPORTED_COMPILER_CHECK)
+    #if defined(__clang__)
+        #if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
+            #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
+        #endif
+    #elif defined(__GNUC__) && !(defined(__ICC) || defined(__INTEL_COMPILER))
+        #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40800
+            #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
+        #endif
+    #endif
+#endif
 
-Exceptions have ids 1xx.
+// C++ language standard detection
+// if the user manually specified the used c++ version this is skipped
+#if !defined(JSON_HAS_CPP_20) && !defined(JSON_HAS_CPP_17) && !defined(JSON_HAS_CPP_14) && !defined(JSON_HAS_CPP_11)
+    #if (defined(__cplusplus) && __cplusplus >= 202002L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L)
+        #define JSON_HAS_CPP_20
+        #define JSON_HAS_CPP_17
+        #define JSON_HAS_CPP_14
+    #elif (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
+        #define JSON_HAS_CPP_17
+        #define JSON_HAS_CPP_14
+    #elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
+        #define JSON_HAS_CPP_14
+    #endif
+    // the cpp 11 flag is always specified because it is the minimal required version
+    #define JSON_HAS_CPP_11
+#endif
 
-name / id                      | example message | description
------------------------------- | --------------- | -------------------------
-json.exception.parse_error.101 | parse error at 2: unexpected end of input; expected string literal | This error indicates a syntax error while deserializing a JSON text. The error message describes that an unexpected token (character) was encountered, and the member @a byte indicates the error position.
-json.exception.parse_error.102 | parse error at 14: missing or wrong low surrogate | JSON uses the `\uxxxx` format to describe Unicode characters. Code points above above 0xFFFF are split into two `\uxxxx` entries ("surrogate pairs"). This error indicates that the surrogate pair is incomplete or contains an invalid code point.
-json.exception.parse_error.103 | parse error: code points above 0x10FFFF are invalid | Unicode supports code points up to 0x10FFFF. Code points above 0x10FFFF are invalid.
-json.exception.parse_error.104 | parse error: JSON patch must be an array of objects | [RFC 6902](https://tools.ietf.org/html/rfc6902) requires a JSON Patch document to be a JSON document that represents an array of objects.
-json.exception.parse_error.105 | parse error: operation must have string member 'op' | An operation of a JSON Patch document must contain exactly one "op" member, whose value indicates the operation to perform. Its value must be one of "add", "remove", "replace", "move", "copy", or "test"; other values are errors.
-json.exception.parse_error.106 | parse error: array index '01' must not begin with '0' | An array index in a JSON Pointer ([RFC 6901](https://tools.ietf.org/html/rfc6901)) may be `0` or any number without a leading `0`.
-json.exception.parse_error.107 | parse error: JSON pointer must be empty or begin with '/' - was: 'foo' | A JSON Pointer must be a Unicode string containing a sequence of zero or more reference tokens, each prefixed by a `/` character.
-json.exception.parse_error.108 | parse error: escape character '~' must be followed with '0' or '1' | In a JSON Pointer, only `~0` and `~1` are valid escape sequences.
-json.exception.parse_error.109 | parse error: array index 'one' is not a number | A JSON Pointer array index must be a number.
-json.exception.parse_error.110 | parse error at 1: cannot read 2 bytes from vector | When parsing CBOR or MessagePack, the byte vector ends before the complete value has been read.
-json.exception.parse_error.112 | parse error at 1: error reading CBOR; last byte: 0xF8 | Not all types of CBOR or MessagePack are supported. This exception occurs if an unsupported byte was read.
-json.exception.parse_error.113 | parse error at 2: expected a CBOR string; last byte: 0x98 | While parsing a map key, a value that is not a string has been read.
-json.exception.parse_error.114 | parse error: Unsupported BSON record type 0x0F | The parsing of the corresponding BSON record type is not implemented (yet).
+// disable documentation warnings on clang
+#if defined(__clang__)
+    #pragma clang diagnostic push
+    #pragma clang diagnostic ignored "-Wdocumentation"
+    #pragma clang diagnostic ignored "-Wdocumentation-unknown-command"
+#endif
 
-@note For an input with n bytes, 1 is the index of the first character and n+1
-      is the index of the terminating null byte or the end of file. This also
-      holds true when reading a byte vector (CBOR or MessagePack).
+// allow to disable exceptions
+#if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND)) && !defined(JSON_NOEXCEPTION)
+    #define JSON_THROW(exception) throw exception
+    #define JSON_TRY try
+    #define JSON_CATCH(exception) catch(exception)
+    #define JSON_INTERNAL_CATCH(exception) catch(exception)
+#else
+    #include <cstdlib>
+    #define JSON_THROW(exception) std::abort()
+    #define JSON_TRY if(true)
+    #define JSON_CATCH(exception) if(false)
+    #define JSON_INTERNAL_CATCH(exception) if(false)
+#endif
 
-@liveexample{The following code shows how a `parse_error` exception can be
-caught.,parse_error}
+// override exception macros
+#if defined(JSON_THROW_USER)
+    #undef JSON_THROW
+    #define JSON_THROW JSON_THROW_USER
+#endif
+#if defined(JSON_TRY_USER)
+    #undef JSON_TRY
+    #define JSON_TRY JSON_TRY_USER
+#endif
+#if defined(JSON_CATCH_USER)
+    #undef JSON_CATCH
+    #define JSON_CATCH JSON_CATCH_USER
+    #undef JSON_INTERNAL_CATCH
+    #define JSON_INTERNAL_CATCH JSON_CATCH_USER
+#endif
+#if defined(JSON_INTERNAL_CATCH_USER)
+    #undef JSON_INTERNAL_CATCH
+    #define JSON_INTERNAL_CATCH JSON_INTERNAL_CATCH_USER
+#endif
 
-@sa @ref exception for the base class of the library exceptions
-@sa @ref invalid_iterator for exceptions indicating errors with iterators
-@sa @ref type_error for exceptions indicating executing a member function with
-                    a wrong type
-@sa @ref out_of_range for exceptions indicating access out of the defined range
-@sa @ref other_error for exceptions indicating other library errors
+// allow to override assert
+#if !defined(JSON_ASSERT)
+    #include <cassert> // assert
+    #define JSON_ASSERT(x) assert(x)
+#endif
 
-@since version 3.0.0
-*/
-class parse_error : public exception
-{
-  public:
-    /*!
-    @brief create a parse error exception
-    @param[in] id_       the id of the exception
-    @param[in] position  the position where the error occurred (or with
-                         chars_read_total=0 if the position cannot be
-                         determined)
-    @param[in] what_arg  the explanatory string
-    @return parse_error object
-    */
-    static parse_error create(int id_, const position_t& pos, const std::string& what_arg)
-    {
-        std::string w = exception::name("parse_error", id_) + "parse error" +
-                        position_string(pos) + ": " + what_arg;
-        return parse_error(id_, pos.chars_read_total, w.c_str());
-    }
+// allow to access some private functions (needed by the test suite)
+#if defined(JSON_TESTS_PRIVATE)
+    #define JSON_PRIVATE_UNLESS_TESTED public
+#else
+    #define JSON_PRIVATE_UNLESS_TESTED private
+#endif
 
-    static parse_error create(int id_, std::size_t byte_, const std::string& what_arg)
-    {
-        std::string w = exception::name("parse_error", id_) + "parse error" +
-                        (byte_ != 0 ? (" at byte " + std::to_string(byte_)) : "") +
-                        ": " + what_arg;
-        return parse_error(id_, byte_, w.c_str());
+/*!
+@brief macro to briefly define a mapping between an enum and JSON
+@def NLOHMANN_JSON_SERIALIZE_ENUM
+@since version 3.4.0
+*/
+#define NLOHMANN_JSON_SERIALIZE_ENUM(ENUM_TYPE, ...)                                            \
+    template<typename BasicJsonType>                                                            \
+    inline void to_json(BasicJsonType& j, const ENUM_TYPE& e)                                   \
+    {                                                                                           \
+        static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!");          \
+        static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__;                     \
+        auto it = std::find_if(std::begin(m), std::end(m),                                      \
+                               [e](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool  \
+        {                                                                                       \
+            return ej_pair.first == e;                                                          \
+        });                                                                                     \
+        j = ((it != std::end(m)) ? it : std::begin(m))->second;                                 \
+    }                                                                                           \
+    template<typename BasicJsonType>                                                            \
+    inline void from_json(const BasicJsonType& j, ENUM_TYPE& e)                                 \
+    {                                                                                           \
+        static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!");          \
+        static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__;                     \
+        auto it = std::find_if(std::begin(m), std::end(m),                                      \
+                               [&j](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
+        {                                                                                       \
+            return ej_pair.second == j;                                                         \
+        });                                                                                     \
+        e = ((it != std::end(m)) ? it : std::begin(m))->first;                                  \
     }
 
-    /*!
-    @brief byte index of the parse error
-
-    The byte index of the last read character in the input file.
+// Ugly macros to avoid uglier copy-paste when specializing basic_json. They
+// may be removed in the future once the class is split.
 
-    @note For an input with n bytes, 1 is the index of the first character and
-          n+1 is the index of the terminating null byte or the end of file.
-          This also holds true when reading a byte vector (CBOR or MessagePack).
-    */
-    const std::size_t byte;
+#define NLOHMANN_BASIC_JSON_TPL_DECLARATION                                \
+    template<template<typename, typename, typename...> class ObjectType,   \
+             template<typename, typename...> class ArrayType,              \
+             class StringType, class BooleanType, class NumberIntegerType, \
+             class NumberUnsignedType, class NumberFloatType,              \
+             template<typename> class AllocatorType,                       \
+             template<typename, typename = void> class JSONSerializer,     \
+             class BinaryType>
 
-  private:
-    parse_error(int id_, std::size_t byte_, const char* what_arg)
-        : exception(id_, what_arg), byte(byte_) {}
+#define NLOHMANN_BASIC_JSON_TPL                                            \
+    basic_json<ObjectType, ArrayType, StringType, BooleanType,             \
+    NumberIntegerType, NumberUnsignedType, NumberFloatType,                \
+    AllocatorType, JSONSerializer, BinaryType>
+
+// Macros to simplify conversion from/to types
+
+#define NLOHMANN_JSON_EXPAND( x ) x
+#define NLOHMANN_JSON_GET_MACRO(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _60, _61, _62, _63, _64, NAME,...) NAME
+#define NLOHMANN_JSON_PASTE(...) NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_GET_MACRO(__VA_ARGS__, \
+        NLOHMANN_JSON_PASTE64, \
+        NLOHMANN_JSON_PASTE63, \
+        NLOHMANN_JSON_PASTE62, \
+        NLOHMANN_JSON_PASTE61, \
+        NLOHMANN_JSON_PASTE60, \
+        NLOHMANN_JSON_PASTE59, \
+        NLOHMANN_JSON_PASTE58, \
+        NLOHMANN_JSON_PASTE57, \
+        NLOHMANN_JSON_PASTE56, \
+        NLOHMANN_JSON_PASTE55, \
+        NLOHMANN_JSON_PASTE54, \
+        NLOHMANN_JSON_PASTE53, \
+        NLOHMANN_JSON_PASTE52, \
+        NLOHMANN_JSON_PASTE51, \
+        NLOHMANN_JSON_PASTE50, \
+        NLOHMANN_JSON_PASTE49, \
+        NLOHMANN_JSON_PASTE48, \
+        NLOHMANN_JSON_PASTE47, \
+        NLOHMANN_JSON_PASTE46, \
+        NLOHMANN_JSON_PASTE45, \
+        NLOHMANN_JSON_PASTE44, \
+        NLOHMANN_JSON_PASTE43, \
+        NLOHMANN_JSON_PASTE42, \
+        NLOHMANN_JSON_PASTE41, \
+        NLOHMANN_JSON_PASTE40, \
+        NLOHMANN_JSON_PASTE39, \
+        NLOHMANN_JSON_PASTE38, \
+        NLOHMANN_JSON_PASTE37, \
+        NLOHMANN_JSON_PASTE36, \
+        NLOHMANN_JSON_PASTE35, \
+        NLOHMANN_JSON_PASTE34, \
+        NLOHMANN_JSON_PASTE33, \
+        NLOHMANN_JSON_PASTE32, \
+        NLOHMANN_JSON_PASTE31, \
+        NLOHMANN_JSON_PASTE30, \
+        NLOHMANN_JSON_PASTE29, \
+        NLOHMANN_JSON_PASTE28, \
+        NLOHMANN_JSON_PASTE27, \
+        NLOHMANN_JSON_PASTE26, \
+        NLOHMANN_JSON_PASTE25, \
+        NLOHMANN_JSON_PASTE24, \
+        NLOHMANN_JSON_PASTE23, \
+        NLOHMANN_JSON_PASTE22, \
+        NLOHMANN_JSON_PASTE21, \
+        NLOHMANN_JSON_PASTE20, \
+        NLOHMANN_JSON_PASTE19, \
+        NLOHMANN_JSON_PASTE18, \
+        NLOHMANN_JSON_PASTE17, \
+        NLOHMANN_JSON_PASTE16, \
+        NLOHMANN_JSON_PASTE15, \
+        NLOHMANN_JSON_PASTE14, \
+        NLOHMANN_JSON_PASTE13, \
+        NLOHMANN_JSON_PASTE12, \
+        NLOHMANN_JSON_PASTE11, \
+        NLOHMANN_JSON_PASTE10, \
+        NLOHMANN_JSON_PASTE9, \
+        NLOHMANN_JSON_PASTE8, \
+        NLOHMANN_JSON_PASTE7, \
+        NLOHMANN_JSON_PASTE6, \
+        NLOHMANN_JSON_PASTE5, \
+        NLOHMANN_JSON_PASTE4, \
+        NLOHMANN_JSON_PASTE3, \
+        NLOHMANN_JSON_PASTE2, \
+        NLOHMANN_JSON_PASTE1)(__VA_ARGS__))
+#define NLOHMANN_JSON_PASTE2(func, v1) func(v1)
+#define NLOHMANN_JSON_PASTE3(func, v1, v2) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE2(func, v2)
+#define NLOHMANN_JSON_PASTE4(func, v1, v2, v3) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE3(func, v2, v3)
+#define NLOHMANN_JSON_PASTE5(func, v1, v2, v3, v4) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE4(func, v2, v3, v4)
+#define NLOHMANN_JSON_PASTE6(func, v1, v2, v3, v4, v5) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE5(func, v2, v3, v4, v5)
+#define NLOHMANN_JSON_PASTE7(func, v1, v2, v3, v4, v5, v6) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE6(func, v2, v3, v4, v5, v6)
+#define NLOHMANN_JSON_PASTE8(func, v1, v2, v3, v4, v5, v6, v7) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE7(func, v2, v3, v4, v5, v6, v7)
+#define NLOHMANN_JSON_PASTE9(func, v1, v2, v3, v4, v5, v6, v7, v8) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE8(func, v2, v3, v4, v5, v6, v7, v8)
+#define NLOHMANN_JSON_PASTE10(func, v1, v2, v3, v4, v5, v6, v7, v8, v9) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE9(func, v2, v3, v4, v5, v6, v7, v8, v9)
+#define NLOHMANN_JSON_PASTE11(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE10(func, v2, v3, v4, v5, v6, v7, v8, v9, v10)
+#define NLOHMANN_JSON_PASTE12(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE11(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11)
+#define NLOHMANN_JSON_PASTE13(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE12(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12)
+#define NLOHMANN_JSON_PASTE14(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE13(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13)
+#define NLOHMANN_JSON_PASTE15(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE14(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14)
+#define NLOHMANN_JSON_PASTE16(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE15(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15)
+#define NLOHMANN_JSON_PASTE17(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE16(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16)
+#define NLOHMANN_JSON_PASTE18(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE17(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17)
+#define NLOHMANN_JSON_PASTE19(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE18(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18)
+#define NLOHMANN_JSON_PASTE20(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE19(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19)
+#define NLOHMANN_JSON_PASTE21(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE20(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20)
+#define NLOHMANN_JSON_PASTE22(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE21(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21)
+#define NLOHMANN_JSON_PASTE23(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE22(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22)
+#define NLOHMANN_JSON_PASTE24(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE23(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23)
+#define NLOHMANN_JSON_PASTE25(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE24(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24)
+#define NLOHMANN_JSON_PASTE26(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE25(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25)
+#define NLOHMANN_JSON_PASTE27(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE26(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26)
+#define NLOHMANN_JSON_PASTE28(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE27(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27)
+#define NLOHMANN_JSON_PASTE29(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE28(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28)
+#define NLOHMANN_JSON_PASTE30(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE29(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29)
+#define NLOHMANN_JSON_PASTE31(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE30(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30)
+#define NLOHMANN_JSON_PASTE32(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE31(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31)
+#define NLOHMANN_JSON_PASTE33(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE32(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32)
+#define NLOHMANN_JSON_PASTE34(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE33(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33)
+#define NLOHMANN_JSON_PASTE35(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE34(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34)
+#define NLOHMANN_JSON_PASTE36(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE35(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35)
+#define NLOHMANN_JSON_PASTE37(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE36(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36)
+#define NLOHMANN_JSON_PASTE38(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE37(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37)
+#define NLOHMANN_JSON_PASTE39(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE38(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38)
+#define NLOHMANN_JSON_PASTE40(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE39(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39)
+#define NLOHMANN_JSON_PASTE41(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE40(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40)
+#define NLOHMANN_JSON_PASTE42(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE41(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41)
+#define NLOHMANN_JSON_PASTE43(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE42(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42)
+#define NLOHMANN_JSON_PASTE44(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE43(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43)
+#define NLOHMANN_JSON_PASTE45(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE44(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44)
+#define NLOHMANN_JSON_PASTE46(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE45(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45)
+#define NLOHMANN_JSON_PASTE47(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE46(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46)
+#define NLOHMANN_JSON_PASTE48(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE47(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47)
+#define NLOHMANN_JSON_PASTE49(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE48(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48)
+#define NLOHMANN_JSON_PASTE50(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE49(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49)
+#define NLOHMANN_JSON_PASTE51(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE50(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50)
+#define NLOHMANN_JSON_PASTE52(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE51(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51)
+#define NLOHMANN_JSON_PASTE53(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE52(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52)
+#define NLOHMANN_JSON_PASTE54(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE53(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53)
+#define NLOHMANN_JSON_PASTE55(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE54(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54)
+#define NLOHMANN_JSON_PASTE56(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE55(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55)
+#define NLOHMANN_JSON_PASTE57(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE56(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56)
+#define NLOHMANN_JSON_PASTE58(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE57(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57)
+#define NLOHMANN_JSON_PASTE59(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE58(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58)
+#define NLOHMANN_JSON_PASTE60(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE59(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59)
+#define NLOHMANN_JSON_PASTE61(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE60(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60)
+#define NLOHMANN_JSON_PASTE62(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60, v61) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE61(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60, v61)
+#define NLOHMANN_JSON_PASTE63(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60, v61, v62) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE62(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60, v61, v62)
+#define NLOHMANN_JSON_PASTE64(func, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60, v61, v62, v63) NLOHMANN_JSON_PASTE2(func, v1) NLOHMANN_JSON_PASTE63(func, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31, v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46, v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60, v61, v62, v63)
+
+#define NLOHMANN_JSON_TO(v1) nlohmann_json_j[#v1] = nlohmann_json_t.v1;
+#define NLOHMANN_JSON_FROM(v1) nlohmann_json_j.at(#v1).get_to(nlohmann_json_t.v1);
 
-    static std::string position_string(const position_t& pos)
-    {
-        return " at line " + std::to_string(pos.lines_read + 1) +
-               ", column " + std::to_string(pos.chars_read_current_line);
-    }
-};
+/*!
+@brief macro
+@def NLOHMANN_DEFINE_TYPE_INTRUSIVE
+@since version 3.9.0
+*/
+#define NLOHMANN_DEFINE_TYPE_INTRUSIVE(Type, ...)  \
+    friend void to_json(nlohmann::json& nlohmann_json_j, const Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_TO, __VA_ARGS__)) } \
+    friend void from_json(const nlohmann::json& nlohmann_json_j, Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_FROM, __VA_ARGS__)) }
 
 /*!
-@brief exception indicating errors with iterators
+@brief macro
+@def NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE
+@since version 3.9.0
+*/
+#define NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(Type, ...)  \
+    inline void to_json(nlohmann::json& nlohmann_json_j, const Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_TO, __VA_ARGS__)) } \
+    inline void from_json(const nlohmann::json& nlohmann_json_j, Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_FROM, __VA_ARGS__)) }
 
-This exception is thrown if iterators passed to a library function do not match
-the expected semantics.
 
-Exceptions have ids 2xx.
+// inspired from https://stackoverflow.com/a/26745591
+// allows to call any std function as if (e.g. with begin):
+// using std::begin; begin(x);
+//
+// it allows using the detected idiom to retrieve the return type
+// of such an expression
+#define NLOHMANN_CAN_CALL_STD_FUNC_IMPL(std_name)                                 \
+    namespace detail {                                                            \
+    using std::std_name;                                                          \
+    \
+    template<typename... T>                                                       \
+    using result_of_##std_name = decltype(std_name(std::declval<T>()...));        \
+    }                                                                             \
+    \
+    namespace detail2 {                                                           \
+    struct std_name##_tag                                                         \
+    {                                                                             \
+    };                                                                            \
+    \
+    template<typename... T>                                                       \
+    std_name##_tag std_name(T&&...);                                              \
+    \
+    template<typename... T>                                                       \
+    using result_of_##std_name = decltype(std_name(std::declval<T>()...));        \
+    \
+    template<typename... T>                                                       \
+    struct would_call_std_##std_name                                              \
+    {                                                                             \
+        static constexpr auto const value = ::nlohmann::detail::                  \
+                                            is_detected_exact<std_name##_tag, result_of_##std_name, T...>::value; \
+    };                                                                            \
+    } /* namespace detail2 */ \
+    \
+    template<typename... T>                                                       \
+    struct would_call_std_##std_name : detail2::would_call_std_##std_name<T...>   \
+    {                                                                             \
+    }
+
+#ifndef JSON_USE_IMPLICIT_CONVERSIONS
+    #define JSON_USE_IMPLICIT_CONVERSIONS 1
+#endif
 
-name / id                           | example message | description
------------------------------------ | --------------- | -------------------------
-json.exception.invalid_iterator.201 | iterators are not compatible | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
-json.exception.invalid_iterator.202 | iterator does not fit current value | In an erase or insert function, the passed iterator @a pos does not belong to the JSON value for which the function was called. It hence does not define a valid position for the deletion/insertion.
-json.exception.invalid_iterator.203 | iterators do not fit current value | Either iterator passed to function @ref erase(IteratorType first, IteratorType last) does not belong to the JSON value from which values shall be erased. It hence does not define a valid range to delete values from.
-json.exception.invalid_iterator.204 | iterators out of range | When an iterator range for a primitive type (number, boolean, or string) is passed to a constructor or an erase function, this range has to be exactly (@ref begin(), @ref end()), because this is the only way the single stored value is expressed. All other ranges are invalid.
-json.exception.invalid_iterator.205 | iterator out of range | When an iterator for a primitive type (number, boolean, or string) is passed to an erase function, the iterator has to be the @ref begin() iterator, because it is the only way to address the stored value. All other iterators are invalid.
-json.exception.invalid_iterator.206 | cannot construct with iterators from null | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) belong to a JSON null value and hence to not define a valid range.
-json.exception.invalid_iterator.207 | cannot use key() for non-object iterators | The key() member function can only be used on iterators belonging to a JSON object, because other types do not have a concept of a key.
-json.exception.invalid_iterator.208 | cannot use operator[] for object iterators | The operator[] to specify a concrete offset cannot be used on iterators belonging to a JSON object, because JSON objects are unordered.
-json.exception.invalid_iterator.209 | cannot use offsets with object iterators | The offset operators (+, -, +=, -=) cannot be used on iterators belonging to a JSON object, because JSON objects are unordered.
-json.exception.invalid_iterator.210 | iterators do not fit | The iterator range passed to the insert function are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
-json.exception.invalid_iterator.211 | passed iterators may not belong to container | The iterator range passed to the insert function must not be a subrange of the container to insert to.
-json.exception.invalid_iterator.212 | cannot compare iterators of different containers | When two iterators are compared, they must belong to the same container.
-json.exception.invalid_iterator.213 | cannot compare order of object iterators | The order of object iterators cannot be compared, because JSON objects are unordered.
-json.exception.invalid_iterator.214 | cannot get value | Cannot get value for iterator: Either the iterator belongs to a null value or it is an iterator to a primitive type (number, boolean, or string), but the iterator is different to @ref begin().
+#if JSON_USE_IMPLICIT_CONVERSIONS
+    #define JSON_EXPLICIT
+#else
+    #define JSON_EXPLICIT explicit
+#endif
 
-@liveexample{The following code shows how an `invalid_iterator` exception can be
-caught.,invalid_iterator}
+#ifndef JSON_DIAGNOSTICS
+    #define JSON_DIAGNOSTICS 0
+#endif
 
-@sa @ref exception for the base class of the library exceptions
-@sa @ref parse_error for exceptions indicating a parse error
-@sa @ref type_error for exceptions indicating executing a member function with
-                    a wrong type
-@sa @ref out_of_range for exceptions indicating access out of the defined range
-@sa @ref other_error for exceptions indicating other library errors
 
-@since version 3.0.0
-*/
-class invalid_iterator : public exception
+namespace nlohmann
+{
+namespace detail
 {
-  public:
-    static invalid_iterator create(int id_, const std::string& what_arg)
-    {
-        std::string w = exception::name("invalid_iterator", id_) + what_arg;
-        return invalid_iterator(id_, w.c_str());
-    }
-
-  private:
-    invalid_iterator(int id_, const char* what_arg)
-        : exception(id_, what_arg) {}
-};
 
 /*!
-@brief exception indicating executing a member function with a wrong type
-
-This exception is thrown in case of a type error; that is, a library function is
-executed on a JSON value whose type does not match the expected semantics.
-
-Exceptions have ids 3xx.
-
-name / id                     | example message | description
------------------------------ | --------------- | -------------------------
-json.exception.type_error.301 | cannot create object from initializer list | To create an object from an initializer list, the initializer list must consist only of a list of pairs whose first element is a string. When this constraint is violated, an array is created instead.
-json.exception.type_error.302 | type must be object, but is array | During implicit or explicit value conversion, the JSON type must be compatible to the target type. For instance, a JSON string can only be converted into string types, but not into numbers or boolean types.
-json.exception.type_error.303 | incompatible ReferenceType for get_ref, actual type is object | To retrieve a reference to a value stored in a @ref basic_json object with @ref get_ref, the type of the reference must match the value type. For instance, for a JSON array, the @a ReferenceType must be @ref array_t&.
-json.exception.type_error.304 | cannot use at() with string | The @ref at() member functions can only be executed for certain JSON types.
-json.exception.type_error.305 | cannot use operator[] with string | The @ref operator[] member functions can only be executed for certain JSON types.
-json.exception.type_error.306 | cannot use value() with string | The @ref value() member functions can only be executed for certain JSON types.
-json.exception.type_error.307 | cannot use erase() with string | The @ref erase() member functions can only be executed for certain JSON types.
-json.exception.type_error.308 | cannot use push_back() with string | The @ref push_back() and @ref operator+= member functions can only be executed for certain JSON types.
-json.exception.type_error.309 | cannot use insert() with | The @ref insert() member functions can only be executed for certain JSON types.
-json.exception.type_error.310 | cannot use swap() with number | The @ref swap() member functions can only be executed for certain JSON types.
-json.exception.type_error.311 | cannot use emplace_back() with string | The @ref emplace_back() member function can only be executed for certain JSON types.
-json.exception.type_error.312 | cannot use update() with string | The @ref update() member functions can only be executed for certain JSON types.
-json.exception.type_error.313 | invalid value to unflatten | The @ref unflatten function converts an object whose keys are JSON Pointers back into an arbitrary nested JSON value. The JSON Pointers must not overlap, because then the resulting value would not be well defined.
-json.exception.type_error.314 | only objects can be unflattened | The @ref unflatten function only works for an object whose keys are JSON Pointers.
-json.exception.type_error.315 | values in object must be primitive | The @ref unflatten function only works for an object whose keys are JSON Pointers and whose values are primitive.
-json.exception.type_error.316 | invalid UTF-8 byte at index 10: 0x7E | The @ref dump function only works with UTF-8 encoded strings; that is, if you assign a `std::string` to a JSON value, make sure it is UTF-8 encoded. |
-json.exception.type_error.317 | JSON value cannot be serialized to requested format | The dynamic type of the object cannot be represented in the requested serialization format (e.g. a raw `true` or `null` JSON object cannot be serialized to BSON) |
+@brief replace all occurrences of a substring by another string
 
-@liveexample{The following code shows how a `type_error` exception can be
-caught.,type_error}
+@param[in,out] s  the string to manipulate; changed so that all
+               occurrences of @a f are replaced with @a t
+@param[in]     f  the substring to replace with @a t
+@param[in]     t  the string to replace @a f
 
-@sa @ref exception for the base class of the library exceptions
-@sa @ref parse_error for exceptions indicating a parse error
-@sa @ref invalid_iterator for exceptions indicating errors with iterators
-@sa @ref out_of_range for exceptions indicating access out of the defined range
-@sa @ref other_error for exceptions indicating other library errors
+@pre The search string @a f must not be empty. **This precondition is
+enforced with an assertion.**
 
-@since version 3.0.0
+@since version 2.0.0
 */
-class type_error : public exception
+inline void replace_substring(std::string& s, const std::string& f,
+                              const std::string& t)
 {
-  public:
-    static type_error create(int id_, const std::string& what_arg)
-    {
-        std::string w = exception::name("type_error", id_) + what_arg;
-        return type_error(id_, w.c_str());
-    }
-
-  private:
-    type_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
-};
+    JSON_ASSERT(!f.empty());
+    for (auto pos = s.find(f);                // find first occurrence of f
+            pos != std::string::npos;         // make sure f was found
+            s.replace(pos, f.size(), t),      // replace with t, and
+            pos = s.find(f, pos + t.size()))  // find next occurrence of f
+    {}
+}
 
 /*!
-@brief exception indicating access out of the defined range
+ * @brief string escaping as described in RFC 6901 (Sect. 4)
+ * @param[in] s string to escape
+ * @return    escaped string
+ *
+ * Note the order of escaping "~" to "~0" and "/" to "~1" is important.
+ */
+inline std::string escape(std::string s)
+{
+    replace_substring(s, "~", "~0");
+    replace_substring(s, "/", "~1");
+    return s;
+}
 
-This exception is thrown in case a library function is called on an input
-parameter that exceeds the expected range, for instance in case of array
-indices or nonexisting object keys.
+/*!
+ * @brief string unescaping as described in RFC 6901 (Sect. 4)
+ * @param[in] s string to unescape
+ * @return    unescaped string
+ *
+ * Note the order of escaping "~1" to "/" and "~0" to "~" is important.
+ */
+static void unescape(std::string& s)
+{
+    replace_substring(s, "~1", "/");
+    replace_substring(s, "~0", "~");
+}
 
-Exceptions have ids 4xx.
+} // namespace detail
+} // namespace nlohmann
 
-name / id                       | example message | description
-------------------------------- | --------------- | -------------------------
-json.exception.out_of_range.401 | array index 3 is out of range | The provided array index @a i is larger than @a size-1.
-json.exception.out_of_range.402 | array index '-' (3) is out of range | The special array index `-` in a JSON Pointer never describes a valid element of the array, but the index past the end. That is, it can only be used to add elements at this position, but not to read it.
-json.exception.out_of_range.403 | key 'foo' not found | The provided key was not found in the JSON object.
-json.exception.out_of_range.404 | unresolved reference token 'foo' | A reference token in a JSON Pointer could not be resolved.
-json.exception.out_of_range.405 | JSON pointer has no parent | The JSON Patch operations 'remove' and 'add' can not be applied to the root element of the JSON value.
-json.exception.out_of_range.406 | number overflow parsing '10E1000' | A parsed number could not be stored as without changing it to NaN or INF.
-json.exception.out_of_range.407 | number overflow serializing '9223372036854775808' | UBJSON and BSON only support integer numbers up to 9223372036854775807. |
-json.exception.out_of_range.408 | excessive array size: 8658170730974374167 | The size (following `#`) of an UBJSON array or object exceeds the maximal capacity. |
-json.exception.out_of_range.409 | BSON key cannot contain code point U+0000 (at byte 2) | Key identifiers to be serialized to BSON cannot contain code point U+0000, since the key is stored as zero-terminated c-string |
+// #include <nlohmann/detail/input/position_t.hpp>
 
-@liveexample{The following code shows how an `out_of_range` exception can be
-caught.,out_of_range}
 
-@sa @ref exception for the base class of the library exceptions
-@sa @ref parse_error for exceptions indicating a parse error
-@sa @ref invalid_iterator for exceptions indicating errors with iterators
-@sa @ref type_error for exceptions indicating executing a member function with
-                    a wrong type
-@sa @ref other_error for exceptions indicating other library errors
+#include <cstddef> // size_t
 
-@since version 3.0.0
-*/
-class out_of_range : public exception
+namespace nlohmann
 {
-  public:
-    static out_of_range create(int id_, const std::string& what_arg)
+namespace detail
+{
+/// struct to capture the start position of the current token
+struct position_t
+{
+    /// the total number of characters read
+    std::size_t chars_read_total = 0;
+    /// the number of characters read in the current line
+    std::size_t chars_read_current_line = 0;
+    /// the number of lines read
+    std::size_t lines_read = 0;
+
+    /// conversion to size_t to preserve SAX interface
+    constexpr operator size_t() const
     {
-        std::string w = exception::name("out_of_range", id_) + what_arg;
-        return out_of_range(id_, w.c_str());
+        return chars_read_total;
     }
-
-  private:
-    out_of_range(int id_, const char* what_arg) : exception(id_, what_arg) {}
 };
 
-/*!
-@brief exception indicating other library errors
-
-This exception is thrown in case of errors that cannot be classified with the
-other exception types.
+} // namespace detail
+} // namespace nlohmann
 
-Exceptions have ids 5xx.
+// #include <nlohmann/detail/macro_scope.hpp>
 
-name / id                      | example message | description
------------------------------- | --------------- | -------------------------
-json.exception.other_error.501 | unsuccessful: {"op":"test","path":"/baz", "value":"bar"} | A JSON Patch operation 'test' failed. The unsuccessful operation is also printed.
 
-@sa @ref exception for the base class of the library exceptions
-@sa @ref parse_error for exceptions indicating a parse error
-@sa @ref invalid_iterator for exceptions indicating errors with iterators
-@sa @ref type_error for exceptions indicating executing a member function with
-                    a wrong type
-@sa @ref out_of_range for exceptions indicating access out of the defined range
+namespace nlohmann
+{
+namespace detail
+{
+////////////////
+// exceptions //
+////////////////
 
-@liveexample{The following code shows how an `other_error` exception can be
-caught.,other_error}
+/*!
+@brief general exception of the @ref basic_json class
 
-@since version 3.0.0
+This class is an extension of `std::exception` objects with a member @a id for
+exception ids. It is used as the base class for all exceptions thrown by the
+@ref basic_json class. This class can hence be used as "wildcard" to catch
+exceptions.
+
+Subclasses:
+- @ref parse_error for exceptions indicating a parse error
+- @ref invalid_iterator for exceptions indicating errors with iterators
+- @ref type_error for exceptions indicating executing a member function with
+                  a wrong type
+- @ref out_of_range for exceptions indicating access out of the defined range
+- @ref other_error for exceptions indicating other library errors
+
+@internal
+@note To have nothrow-copy-constructible exceptions, we internally use
+      `std::runtime_error` which can cope with arbitrary-length error messages.
+      Intermediate strings are built with static functions and then passed to
+      the actual constructor.
+@endinternal
+
+@liveexample{The following code shows how arbitrary library exceptions can be
+caught.,exception}
+
+@since version 3.0.0
 */
-class other_error : public exception
+class exception : public std::exception
 {
   public:
-    static other_error create(int id_, const std::string& what_arg)
+    /// returns the explanatory string
+    const char* what() const noexcept override
     {
-        std::string w = exception::name("other_error", id_) + what_arg;
-        return other_error(id_, w.c_str());
+        return m.what();
     }
 
-  private:
-    other_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
-};
-}  // namespace detail
-}  // namespace nlohmann
-
-// #include <nlohmann/detail/value_t.hpp>
+    /// the id of the exception
+    const int id; // NOLINT(cppcoreguidelines-non-private-member-variables-in-classes)
 
+  protected:
+    JSON_HEDLEY_NON_NULL(3)
+    exception(int id_, const char* what_arg) : id(id_), m(what_arg) {}
 
-#include <array> // array
-#include <ciso646> // and
-#include <cstddef> // size_t
-#include <cstdint> // uint8_t
+    static std::string name(const std::string& ename, int id_)
+    {
+        return "[json.exception." + ename + "." + std::to_string(id_) + "] ";
+    }
 
-namespace nlohmann
-{
-namespace detail
-{
-///////////////////////////
-// JSON type enumeration //
-///////////////////////////
+    template<typename BasicJsonType>
+    static std::string diagnostics(const BasicJsonType& leaf_element)
+    {
+#if JSON_DIAGNOSTICS
+        std::vector<std::string> tokens;
+        for (const auto* current = &leaf_element; current->m_parent != nullptr; current = current->m_parent)
+        {
+            switch (current->m_parent->type())
+            {
+                case value_t::array:
+                {
+                    for (std::size_t i = 0; i < current->m_parent->m_value.array->size(); ++i)
+                    {
+                        if (&current->m_parent->m_value.array->operator[](i) == current)
+                        {
+                            tokens.emplace_back(std::to_string(i));
+                            break;
+                        }
+                    }
+                    break;
+                }
 
-/*!
-@brief the JSON type enumeration
+                case value_t::object:
+                {
+                    for (const auto& element : *current->m_parent->m_value.object)
+                    {
+                        if (&element.second == current)
+                        {
+                            tokens.emplace_back(element.first.c_str());
+                            break;
+                        }
+                    }
+                    break;
+                }
 
-This enumeration collects the different JSON types. It is internally used to
-distinguish the stored values, and the functions @ref basic_json::is_null(),
-@ref basic_json::is_object(), @ref basic_json::is_array(),
-@ref basic_json::is_string(), @ref basic_json::is_boolean(),
-@ref basic_json::is_number() (with @ref basic_json::is_number_integer(),
-@ref basic_json::is_number_unsigned(), and @ref basic_json::is_number_float()),
-@ref basic_json::is_discarded(), @ref basic_json::is_primitive(), and
-@ref basic_json::is_structured() rely on it.
+                case value_t::null: // LCOV_EXCL_LINE
+                case value_t::string: // LCOV_EXCL_LINE
+                case value_t::boolean: // LCOV_EXCL_LINE
+                case value_t::number_integer: // LCOV_EXCL_LINE
+                case value_t::number_unsigned: // LCOV_EXCL_LINE
+                case value_t::number_float: // LCOV_EXCL_LINE
+                case value_t::binary: // LCOV_EXCL_LINE
+                case value_t::discarded: // LCOV_EXCL_LINE
+                default:   // LCOV_EXCL_LINE
+                    break; // LCOV_EXCL_LINE
+            }
+        }
 
-@note There are three enumeration entries (number_integer, number_unsigned, and
-number_float), because the library distinguishes these three types for numbers:
-@ref basic_json::number_unsigned_t is used for unsigned integers,
-@ref basic_json::number_integer_t is used for signed integers, and
-@ref basic_json::number_float_t is used for floating-point numbers or to
-approximate integers which do not fit in the limits of their respective type.
+        if (tokens.empty())
+        {
+            return "";
+        }
 
-@sa @ref basic_json::basic_json(const value_t value_type) -- create a JSON
-value with the default value for a given type
+        return "(" + std::accumulate(tokens.rbegin(), tokens.rend(), std::string{},
+                                     [](const std::string & a, const std::string & b)
+        {
+            return a + "/" + detail::escape(b);
+        }) + ") ";
+#else
+        static_cast<void>(leaf_element);
+        return "";
+#endif
+    }
 
-@since version 1.0.0
-*/
-enum class value_t : std::uint8_t
-{
-    null,             ///< null value
-    object,           ///< object (unordered set of name/value pairs)
-    array,            ///< array (ordered collection of values)
-    string,           ///< string value
-    boolean,          ///< boolean value
-    number_integer,   ///< number value (signed integer)
-    number_unsigned,  ///< number value (unsigned integer)
-    number_float,     ///< number value (floating-point)
-    discarded         ///< discarded by the the parser callback function
+  private:
+    /// an exception object as storage for error messages
+    std::runtime_error m;
 };
 
 /*!
-@brief comparison operator for JSON types
-
-Returns an ordering that is similar to Python:
-- order: null < boolean < number < object < array < string
-- furthermore, each type is not smaller than itself
-- discarded values are not comparable
-
-@since version 1.0.0
-*/
-inline bool operator<(const value_t lhs, const value_t rhs) noexcept
-{
-    static constexpr std::array<std::uint8_t, 8> order = {{
-            0 /* null */, 3 /* object */, 4 /* array */, 5 /* string */,
-            1 /* boolean */, 2 /* integer */, 2 /* unsigned */, 2 /* float */
-        }
-    };
-
-    const auto l_index = static_cast<std::size_t>(lhs);
-    const auto r_index = static_cast<std::size_t>(rhs);
-    return l_index < order.size() and r_index < order.size() and order[l_index] < order[r_index];
-}
-}  // namespace detail
-}  // namespace nlohmann
-
-// #include <nlohmann/detail/conversions/from_json.hpp>
-
+@brief exception indicating a parse error
 
-#include <algorithm> // transform
-#include <array> // array
-#include <ciso646> // and, not
-#include <forward_list> // forward_list
-#include <iterator> // inserter, front_inserter, end
-#include <map> // map
-#include <string> // string
-#include <tuple> // tuple, make_tuple
-#include <type_traits> // is_arithmetic, is_same, is_enum, underlying_type, is_convertible
-#include <unordered_map> // unordered_map
-#include <utility> // pair, declval
-#include <valarray> // valarray
+This exception is thrown by the library when a parse error occurs. Parse errors
+can occur during the deserialization of JSON text, CBOR, MessagePack, as well
+as when using JSON Patch.
 
-// #include <nlohmann/detail/exceptions.hpp>
+Member @a byte holds the byte index of the last read character in the input
+file.
 
-// #include <nlohmann/detail/macro_scope.hpp>
+Exceptions have ids 1xx.
 
-// #include <nlohmann/detail/meta/cpp_future.hpp>
+name / id                      | example message | description
+------------------------------ | --------------- | -------------------------
+json.exception.parse_error.101 | parse error at 2: unexpected end of input; expected string literal | This error indicates a syntax error while deserializing a JSON text. The error message describes that an unexpected token (character) was encountered, and the member @a byte indicates the error position.
+json.exception.parse_error.102 | parse error at 14: missing or wrong low surrogate | JSON uses the `\uxxxx` format to describe Unicode characters. Code points above above 0xFFFF are split into two `\uxxxx` entries ("surrogate pairs"). This error indicates that the surrogate pair is incomplete or contains an invalid code point.
+json.exception.parse_error.103 | parse error: code points above 0x10FFFF are invalid | Unicode supports code points up to 0x10FFFF. Code points above 0x10FFFF are invalid.
+json.exception.parse_error.104 | parse error: JSON patch must be an array of objects | [RFC 6902](https://tools.ietf.org/html/rfc6902) requires a JSON Patch document to be a JSON document that represents an array of objects.
+json.exception.parse_error.105 | parse error: operation must have string member 'op' | An operation of a JSON Patch document must contain exactly one "op" member, whose value indicates the operation to perform. Its value must be one of "add", "remove", "replace", "move", "copy", or "test"; other values are errors.
+json.exception.parse_error.106 | parse error: array index '01' must not begin with '0' | An array index in a JSON Pointer ([RFC 6901](https://tools.ietf.org/html/rfc6901)) may be `0` or any number without a leading `0`.
+json.exception.parse_error.107 | parse error: JSON pointer must be empty or begin with '/' - was: 'foo' | A JSON Pointer must be a Unicode string containing a sequence of zero or more reference tokens, each prefixed by a `/` character.
+json.exception.parse_error.108 | parse error: escape character '~' must be followed with '0' or '1' | In a JSON Pointer, only `~0` and `~1` are valid escape sequences.
+json.exception.parse_error.109 | parse error: array index 'one' is not a number | A JSON Pointer array index must be a number.
+json.exception.parse_error.110 | parse error at 1: cannot read 2 bytes from vector | When parsing CBOR or MessagePack, the byte vector ends before the complete value has been read.
+json.exception.parse_error.112 | parse error at 1: error reading CBOR; last byte: 0xF8 | Not all types of CBOR or MessagePack are supported. This exception occurs if an unsupported byte was read.
+json.exception.parse_error.113 | parse error at 2: expected a CBOR string; last byte: 0x98 | While parsing a map key, a value that is not a string has been read.
+json.exception.parse_error.114 | parse error: Unsupported BSON record type 0x0F | The parsing of the corresponding BSON record type is not implemented (yet).
+json.exception.parse_error.115 | parse error at byte 5: syntax error while parsing UBJSON high-precision number: invalid number text: 1A | A UBJSON high-precision number could not be parsed.
 
-// #include <nlohmann/detail/meta/type_traits.hpp>
+@note For an input with n bytes, 1 is the index of the first character and n+1
+      is the index of the terminating null byte or the end of file. This also
+      holds true when reading a byte vector (CBOR or MessagePack).
 
-// #include <nlohmann/detail/value_t.hpp>
+@liveexample{The following code shows how a `parse_error` exception can be
+caught.,parse_error}
 
+@sa - @ref exception for the base class of the library exceptions
+@sa - @ref invalid_iterator for exceptions indicating errors with iterators
+@sa - @ref type_error for exceptions indicating executing a member function with
+                    a wrong type
+@sa - @ref out_of_range for exceptions indicating access out of the defined range
+@sa - @ref other_error for exceptions indicating other library errors
 
-namespace nlohmann
-{
-namespace detail
-{
-template<typename BasicJsonType>
-void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
+@since version 3.0.0
+*/
+class parse_error : public exception
 {
-    if (JSON_UNLIKELY(not j.is_null()))
+  public:
+    /*!
+    @brief create a parse error exception
+    @param[in] id_       the id of the exception
+    @param[in] pos       the position where the error occurred (or with
+                         chars_read_total=0 if the position cannot be
+                         determined)
+    @param[in] what_arg  the explanatory string
+    @return parse_error object
+    */
+    template<typename BasicJsonType>
+    static parse_error create(int id_, const position_t& pos, const std::string& what_arg, const BasicJsonType& context)
     {
-        JSON_THROW(type_error::create(302, "type must be null, but is " + std::string(j.type_name())));
+        std::string w = exception::name("parse_error", id_) + "parse error" +
+                        position_string(pos) + ": " + exception::diagnostics(context) + what_arg;
+        return parse_error(id_, pos.chars_read_total, w.c_str());
     }
-    n = nullptr;
-}
 
-// overloads for basic_json template parameters
-template<typename BasicJsonType, typename ArithmeticType,
-         enable_if_t<std::is_arithmetic<ArithmeticType>::value and
-                     not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
-                     int> = 0>
-void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
-{
-    switch (static_cast<value_t>(j))
+    template<typename BasicJsonType>
+    static parse_error create(int id_, std::size_t byte_, const std::string& what_arg, const BasicJsonType& context)
     {
-        case value_t::number_unsigned:
-        {
-            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
-            break;
-        }
-        case value_t::number_integer:
-        {
-            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
-            break;
-        }
-        case value_t::number_float:
-        {
-            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
-            break;
-        }
-
-        default:
-            JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
+        std::string w = exception::name("parse_error", id_) + "parse error" +
+                        (byte_ != 0 ? (" at byte " + std::to_string(byte_)) : "") +
+                        ": " + exception::diagnostics(context) + what_arg;
+        return parse_error(id_, byte_, w.c_str());
     }
-}
 
-template<typename BasicJsonType>
-void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
-{
-    if (JSON_UNLIKELY(not j.is_boolean()))
+    /*!
+    @brief byte index of the parse error
+
+    The byte index of the last read character in the input file.
+
+    @note For an input with n bytes, 1 is the index of the first character and
+          n+1 is the index of the terminating null byte or the end of file.
+          This also holds true when reading a byte vector (CBOR or MessagePack).
+    */
+    const std::size_t byte;
+
+  private:
+    parse_error(int id_, std::size_t byte_, const char* what_arg)
+        : exception(id_, what_arg), byte(byte_) {}
+
+    static std::string position_string(const position_t& pos)
     {
-        JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(j.type_name())));
+        return " at line " + std::to_string(pos.lines_read + 1) +
+               ", column " + std::to_string(pos.chars_read_current_line);
     }
-    b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
-}
+};
 
-template<typename BasicJsonType>
-void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s)
-{
-    if (JSON_UNLIKELY(not j.is_string()))
-    {
-        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
-    }
-    s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
-}
+/*!
+@brief exception indicating errors with iterators
 
-template <
-    typename BasicJsonType, typename ConstructibleStringType,
-    enable_if_t <
-        is_constructible_string_type<BasicJsonType, ConstructibleStringType>::value and
-        not std::is_same<typename BasicJsonType::string_t,
-                         ConstructibleStringType>::value,
-        int > = 0 >
-void from_json(const BasicJsonType& j, ConstructibleStringType& s)
+This exception is thrown if iterators passed to a library function do not match
+the expected semantics.
+
+Exceptions have ids 2xx.
+
+name / id                           | example message | description
+----------------------------------- | --------------- | -------------------------
+json.exception.invalid_iterator.201 | iterators are not compatible | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
+json.exception.invalid_iterator.202 | iterator does not fit current value | In an erase or insert function, the passed iterator @a pos does not belong to the JSON value for which the function was called. It hence does not define a valid position for the deletion/insertion.
+json.exception.invalid_iterator.203 | iterators do not fit current value | Either iterator passed to function @ref erase(IteratorType first, IteratorType last) does not belong to the JSON value from which values shall be erased. It hence does not define a valid range to delete values from.
+json.exception.invalid_iterator.204 | iterators out of range | When an iterator range for a primitive type (number, boolean, or string) is passed to a constructor or an erase function, this range has to be exactly (@ref begin(), @ref end()), because this is the only way the single stored value is expressed. All other ranges are invalid.
+json.exception.invalid_iterator.205 | iterator out of range | When an iterator for a primitive type (number, boolean, or string) is passed to an erase function, the iterator has to be the @ref begin() iterator, because it is the only way to address the stored value. All other iterators are invalid.
+json.exception.invalid_iterator.206 | cannot construct with iterators from null | The iterators passed to constructor @ref basic_json(InputIT first, InputIT last) belong to a JSON null value and hence to not define a valid range.
+json.exception.invalid_iterator.207 | cannot use key() for non-object iterators | The key() member function can only be used on iterators belonging to a JSON object, because other types do not have a concept of a key.
+json.exception.invalid_iterator.208 | cannot use operator[] for object iterators | The operator[] to specify a concrete offset cannot be used on iterators belonging to a JSON object, because JSON objects are unordered.
+json.exception.invalid_iterator.209 | cannot use offsets with object iterators | The offset operators (+, -, +=, -=) cannot be used on iterators belonging to a JSON object, because JSON objects are unordered.
+json.exception.invalid_iterator.210 | iterators do not fit | The iterator range passed to the insert function are not compatible, meaning they do not belong to the same container. Therefore, the range (@a first, @a last) is invalid.
+json.exception.invalid_iterator.211 | passed iterators may not belong to container | The iterator range passed to the insert function must not be a subrange of the container to insert to.
+json.exception.invalid_iterator.212 | cannot compare iterators of different containers | When two iterators are compared, they must belong to the same container.
+json.exception.invalid_iterator.213 | cannot compare order of object iterators | The order of object iterators cannot be compared, because JSON objects are unordered.
+json.exception.invalid_iterator.214 | cannot get value | Cannot get value for iterator: Either the iterator belongs to a null value or it is an iterator to a primitive type (number, boolean, or string), but the iterator is different to @ref begin().
+
+@liveexample{The following code shows how an `invalid_iterator` exception can be
+caught.,invalid_iterator}
+
+@sa - @ref exception for the base class of the library exceptions
+@sa - @ref parse_error for exceptions indicating a parse error
+@sa - @ref type_error for exceptions indicating executing a member function with
+                    a wrong type
+@sa - @ref out_of_range for exceptions indicating access out of the defined range
+@sa - @ref other_error for exceptions indicating other library errors
+
+@since version 3.0.0
+*/
+class invalid_iterator : public exception
 {
-    if (JSON_UNLIKELY(not j.is_string()))
+  public:
+    template<typename BasicJsonType>
+    static invalid_iterator create(int id_, const std::string& what_arg, const BasicJsonType& context)
     {
-        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
+        std::string w = exception::name("invalid_iterator", id_) + exception::diagnostics(context) + what_arg;
+        return invalid_iterator(id_, w.c_str());
     }
 
-    s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
-}
+  private:
+    JSON_HEDLEY_NON_NULL(3)
+    invalid_iterator(int id_, const char* what_arg)
+        : exception(id_, what_arg) {}
+};
 
-template<typename BasicJsonType>
-void from_json(const BasicJsonType& j, typename BasicJsonType::number_float_t& val)
-{
-    get_arithmetic_value(j, val);
-}
+/*!
+@brief exception indicating executing a member function with a wrong type
 
-template<typename BasicJsonType>
-void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val)
-{
-    get_arithmetic_value(j, val);
-}
+This exception is thrown in case of a type error; that is, a library function is
+executed on a JSON value whose type does not match the expected semantics.
 
-template<typename BasicJsonType>
-void from_json(const BasicJsonType& j, typename BasicJsonType::number_integer_t& val)
-{
-    get_arithmetic_value(j, val);
-}
+Exceptions have ids 3xx.
 
-template<typename BasicJsonType, typename EnumType,
-         enable_if_t<std::is_enum<EnumType>::value, int> = 0>
-void from_json(const BasicJsonType& j, EnumType& e)
-{
-    typename std::underlying_type<EnumType>::type val;
-    get_arithmetic_value(j, val);
-    e = static_cast<EnumType>(val);
-}
+name / id                     | example message | description
+----------------------------- | --------------- | -------------------------
+json.exception.type_error.301 | cannot create object from initializer list | To create an object from an initializer list, the initializer list must consist only of a list of pairs whose first element is a string. When this constraint is violated, an array is created instead.
+json.exception.type_error.302 | type must be object, but is array | During implicit or explicit value conversion, the JSON type must be compatible to the target type. For instance, a JSON string can only be converted into string types, but not into numbers or boolean types.
+json.exception.type_error.303 | incompatible ReferenceType for get_ref, actual type is object | To retrieve a reference to a value stored in a @ref basic_json object with @ref get_ref, the type of the reference must match the value type. For instance, for a JSON array, the @a ReferenceType must be @ref array_t &.
+json.exception.type_error.304 | cannot use at() with string | The @ref at() member functions can only be executed for certain JSON types.
+json.exception.type_error.305 | cannot use operator[] with string | The @ref operator[] member functions can only be executed for certain JSON types.
+json.exception.type_error.306 | cannot use value() with string | The @ref value() member functions can only be executed for certain JSON types.
+json.exception.type_error.307 | cannot use erase() with string | The @ref erase() member functions can only be executed for certain JSON types.
+json.exception.type_error.308 | cannot use push_back() with string | The @ref push_back() and @ref operator+= member functions can only be executed for certain JSON types.
+json.exception.type_error.309 | cannot use insert() with | The @ref insert() member functions can only be executed for certain JSON types.
+json.exception.type_error.310 | cannot use swap() with number | The @ref swap() member functions can only be executed for certain JSON types.
+json.exception.type_error.311 | cannot use emplace_back() with string | The @ref emplace_back() member function can only be executed for certain JSON types.
+json.exception.type_error.312 | cannot use update() with string | The @ref update() member functions can only be executed for certain JSON types.
+json.exception.type_error.313 | invalid value to unflatten | The @ref unflatten function converts an object whose keys are JSON Pointers back into an arbitrary nested JSON value. The JSON Pointers must not overlap, because then the resulting value would not be well defined.
+json.exception.type_error.314 | only objects can be unflattened | The @ref unflatten function only works for an object whose keys are JSON Pointers.
+json.exception.type_error.315 | values in object must be primitive | The @ref unflatten function only works for an object whose keys are JSON Pointers and whose values are primitive.
+json.exception.type_error.316 | invalid UTF-8 byte at index 10: 0x7E | The @ref dump function only works with UTF-8 encoded strings; that is, if you assign a `std::string` to a JSON value, make sure it is UTF-8 encoded. |
+json.exception.type_error.317 | JSON value cannot be serialized to requested format | The dynamic type of the object cannot be represented in the requested serialization format (e.g. a raw `true` or `null` JSON object cannot be serialized to BSON) |
 
-// forward_list doesn't have an insert method
-template<typename BasicJsonType, typename T, typename Allocator,
-         enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
-void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
-{
-    if (JSON_UNLIKELY(not j.is_array()))
-    {
-        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
-    }
-    std::transform(j.rbegin(), j.rend(),
-                   std::front_inserter(l), [](const BasicJsonType & i)
-    {
-        return i.template get<T>();
-    });
-}
+@liveexample{The following code shows how a `type_error` exception can be
+caught.,type_error}
 
-// valarray doesn't have an insert method
-template<typename BasicJsonType, typename T,
-         enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
-void from_json(const BasicJsonType& j, std::valarray<T>& l)
+@sa - @ref exception for the base class of the library exceptions
+@sa - @ref parse_error for exceptions indicating a parse error
+@sa - @ref invalid_iterator for exceptions indicating errors with iterators
+@sa - @ref out_of_range for exceptions indicating access out of the defined range
+@sa - @ref other_error for exceptions indicating other library errors
+
+@since version 3.0.0
+*/
+class type_error : public exception
 {
-    if (JSON_UNLIKELY(not j.is_array()))
+  public:
+    template<typename BasicJsonType>
+    static type_error create(int id_, const std::string& what_arg, const BasicJsonType& context)
     {
-        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
+        std::string w = exception::name("type_error", id_) + exception::diagnostics(context) + what_arg;
+        return type_error(id_, w.c_str());
     }
-    l.resize(j.size());
-    std::copy(j.m_value.array->begin(), j.m_value.array->end(), std::begin(l));
-}
 
-template<typename BasicJsonType>
-void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType::array_t& arr, priority_tag<3> /*unused*/)
-{
-    arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
-}
+  private:
+    JSON_HEDLEY_NON_NULL(3)
+    type_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
+};
 
-template <typename BasicJsonType, typename T, std::size_t N>
-auto from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr,
-                          priority_tag<2> /*unused*/)
--> decltype(j.template get<T>(), void())
-{
-    for (std::size_t i = 0; i < N; ++i)
-    {
-        arr[i] = j.at(i).template get<T>();
-    }
-}
+/*!
+@brief exception indicating access out of the defined range
 
-template<typename BasicJsonType, typename ConstructibleArrayType>
-auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, priority_tag<1> /*unused*/)
--> decltype(
-    arr.reserve(std::declval<typename ConstructibleArrayType::size_type>()),
-    j.template get<typename ConstructibleArrayType::value_type>(),
-    void())
-{
-    using std::end;
+This exception is thrown in case a library function is called on an input
+parameter that exceeds the expected range, for instance in case of array
+indices or nonexisting object keys.
 
-    arr.reserve(j.size());
-    std::transform(j.begin(), j.end(),
-                   std::inserter(arr, end(arr)), [](const BasicJsonType & i)
-    {
-        // get<BasicJsonType>() returns *this, this won't call a from_json
-        // method when value_type is BasicJsonType
-        return i.template get<typename ConstructibleArrayType::value_type>();
-    });
-}
+Exceptions have ids 4xx.
 
-template <typename BasicJsonType, typename ConstructibleArrayType>
-void from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr,
-                          priority_tag<0> /*unused*/)
-{
-    using std::end;
+name / id                       | example message | description
+------------------------------- | --------------- | -------------------------
+json.exception.out_of_range.401 | array index 3 is out of range | The provided array index @a i is larger than @a size-1.
+json.exception.out_of_range.402 | array index '-' (3) is out of range | The special array index `-` in a JSON Pointer never describes a valid element of the array, but the index past the end. That is, it can only be used to add elements at this position, but not to read it.
+json.exception.out_of_range.403 | key 'foo' not found | The provided key was not found in the JSON object.
+json.exception.out_of_range.404 | unresolved reference token 'foo' | A reference token in a JSON Pointer could not be resolved.
+json.exception.out_of_range.405 | JSON pointer has no parent | The JSON Patch operations 'remove' and 'add' can not be applied to the root element of the JSON value.
+json.exception.out_of_range.406 | number overflow parsing '10E1000' | A parsed number could not be stored as without changing it to NaN or INF.
+json.exception.out_of_range.407 | number overflow serializing '9223372036854775808' | UBJSON and BSON only support integer numbers up to 9223372036854775807. (until version 3.8.0) |
+json.exception.out_of_range.408 | excessive array size: 8658170730974374167 | The size (following `#`) of an UBJSON array or object exceeds the maximal capacity. |
+json.exception.out_of_range.409 | BSON key cannot contain code point U+0000 (at byte 2) | Key identifiers to be serialized to BSON cannot contain code point U+0000, since the key is stored as zero-terminated c-string |
 
-    std::transform(
-        j.begin(), j.end(), std::inserter(arr, end(arr)),
-        [](const BasicJsonType & i)
-    {
-        // get<BasicJsonType>() returns *this, this won't call a from_json
-        // method when value_type is BasicJsonType
-        return i.template get<typename ConstructibleArrayType::value_type>();
-    });
-}
+@liveexample{The following code shows how an `out_of_range` exception can be
+caught.,out_of_range}
 
-template <typename BasicJsonType, typename ConstructibleArrayType,
-          enable_if_t <
-              is_constructible_array_type<BasicJsonType, ConstructibleArrayType>::value and
-              not is_constructible_object_type<BasicJsonType, ConstructibleArrayType>::value and
-              not is_constructible_string_type<BasicJsonType, ConstructibleArrayType>::value and
-              not is_basic_json<ConstructibleArrayType>::value,
-              int > = 0 >
+@sa - @ref exception for the base class of the library exceptions
+@sa - @ref parse_error for exceptions indicating a parse error
+@sa - @ref invalid_iterator for exceptions indicating errors with iterators
+@sa - @ref type_error for exceptions indicating executing a member function with
+                    a wrong type
+@sa - @ref other_error for exceptions indicating other library errors
 
-auto from_json(const BasicJsonType& j, ConstructibleArrayType& arr)
--> decltype(from_json_array_impl(j, arr, priority_tag<3> {}),
-j.template get<typename ConstructibleArrayType::value_type>(),
-void())
+@since version 3.0.0
+*/
+class out_of_range : public exception
 {
-    if (JSON_UNLIKELY(not j.is_array()))
+  public:
+    template<typename BasicJsonType>
+    static out_of_range create(int id_, const std::string& what_arg, const BasicJsonType& context)
     {
-        JSON_THROW(type_error::create(302, "type must be array, but is " +
-                                      std::string(j.type_name())));
+        std::string w = exception::name("out_of_range", id_) + exception::diagnostics(context) + what_arg;
+        return out_of_range(id_, w.c_str());
     }
 
-    from_json_array_impl(j, arr, priority_tag<3> {});
-}
+  private:
+    JSON_HEDLEY_NON_NULL(3)
+    out_of_range(int id_, const char* what_arg) : exception(id_, what_arg) {}
+};
 
-template<typename BasicJsonType, typename ConstructibleObjectType,
-         enable_if_t<is_constructible_object_type<BasicJsonType, ConstructibleObjectType>::value, int> = 0>
-void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
+/*!
+@brief exception indicating other library errors
+
+This exception is thrown in case of errors that cannot be classified with the
+other exception types.
+
+Exceptions have ids 5xx.
+
+name / id                      | example message | description
+------------------------------ | --------------- | -------------------------
+json.exception.other_error.501 | unsuccessful: {"op":"test","path":"/baz", "value":"bar"} | A JSON Patch operation 'test' failed. The unsuccessful operation is also printed.
+
+@sa - @ref exception for the base class of the library exceptions
+@sa - @ref parse_error for exceptions indicating a parse error
+@sa - @ref invalid_iterator for exceptions indicating errors with iterators
+@sa - @ref type_error for exceptions indicating executing a member function with
+                    a wrong type
+@sa - @ref out_of_range for exceptions indicating access out of the defined range
+
+@liveexample{The following code shows how an `other_error` exception can be
+caught.,other_error}
+
+@since version 3.0.0
+*/
+class other_error : public exception
 {
-    if (JSON_UNLIKELY(not j.is_object()))
+  public:
+    template<typename BasicJsonType>
+    static other_error create(int id_, const std::string& what_arg, const BasicJsonType& context)
     {
-        JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name())));
+        std::string w = exception::name("other_error", id_) + exception::diagnostics(context) + what_arg;
+        return other_error(id_, w.c_str());
     }
 
-    auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
-    using value_type = typename ConstructibleObjectType::value_type;
-    std::transform(
-        inner_object->begin(), inner_object->end(),
-        std::inserter(obj, obj.begin()),
-        [](typename BasicJsonType::object_t::value_type const & p)
-    {
-        return value_type(p.first, p.second.template get<typename ConstructibleObjectType::mapped_type>());
-    });
-}
+  private:
+    JSON_HEDLEY_NON_NULL(3)
+    other_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
+};
+}  // namespace detail
+}  // namespace nlohmann
 
-// overload for arithmetic types, not chosen for basic_json template arguments
-// (BooleanType, etc..); note: Is it really necessary to provide explicit
-// overloads for boolean_t etc. in case of a custom BooleanType which is not
-// an arithmetic type?
-template<typename BasicJsonType, typename ArithmeticType,
-         enable_if_t <
-             std::is_arithmetic<ArithmeticType>::value and
-             not std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value and
-             not std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value and
-             not std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value and
-             not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
-             int> = 0>
-void from_json(const BasicJsonType& j, ArithmeticType& val)
-{
-    switch (static_cast<value_t>(j))
-    {
-        case value_t::number_unsigned:
-        {
-            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
-            break;
-        }
-        case value_t::number_integer:
-        {
-            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
-            break;
-        }
-        case value_t::number_float:
-        {
-            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
-            break;
-        }
-        case value_t::boolean:
-        {
-            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>());
-            break;
-        }
+// #include <nlohmann/detail/macro_scope.hpp>
 
-        default:
-            JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
-    }
-}
+// #include <nlohmann/detail/meta/cpp_future.hpp>
 
-template<typename BasicJsonType, typename A1, typename A2>
-void from_json(const BasicJsonType& j, std::pair<A1, A2>& p)
-{
-    p = {j.at(0).template get<A1>(), j.at(1).template get<A2>()};
-}
 
-template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
-void from_json_tuple_impl(const BasicJsonType& j, Tuple& t, index_sequence<Idx...> /*unused*/)
-{
-    t = std::make_tuple(j.at(Idx).template get<typename std::tuple_element<Idx, Tuple>::type>()...);
-}
+#include <cstddef> // size_t
+#include <type_traits> // conditional, enable_if, false_type, integral_constant, is_constructible, is_integral, is_same, remove_cv, remove_reference, true_type
+#include <utility> // index_sequence, make_index_sequence, index_sequence_for
 
-template<typename BasicJsonType, typename... Args>
-void from_json(const BasicJsonType& j, std::tuple<Args...>& t)
+// #include <nlohmann/detail/macro_scope.hpp>
+
+
+namespace nlohmann
+{
+namespace detail
 {
-    from_json_tuple_impl(j, t, index_sequence_for<Args...> {});
-}
 
-template <typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
-          typename = enable_if_t<not std::is_constructible<
-                                     typename BasicJsonType::string_t, Key>::value>>
-void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>& m)
+template<typename T>
+using uncvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type;
+
+#ifdef JSON_HAS_CPP_14
+
+// the following utilities are natively available in C++14
+using std::enable_if_t;
+using std::index_sequence;
+using std::make_index_sequence;
+using std::index_sequence_for;
+
+#else
+
+// alias templates to reduce boilerplate
+template<bool B, typename T = void>
+using enable_if_t = typename std::enable_if<B, T>::type;
+
+// The following code is taken from https://github.com/abseil/abseil-cpp/blob/10cb35e459f5ecca5b2ff107635da0bfa41011b4/absl/utility/utility.h
+// which is part of Google Abseil (https://github.com/abseil/abseil-cpp), licensed under the Apache License 2.0.
+
+//// START OF CODE FROM GOOGLE ABSEIL
+
+// integer_sequence
+//
+// Class template representing a compile-time integer sequence. An instantiation
+// of `integer_sequence<T, Ints...>` has a sequence of integers encoded in its
+// type through its template arguments (which is a common need when
+// working with C++11 variadic templates). `absl::integer_sequence` is designed
+// to be a drop-in replacement for C++14's `std::integer_sequence`.
+//
+// Example:
+//
+//   template< class T, T... Ints >
+//   void user_function(integer_sequence<T, Ints...>);
+//
+//   int main()
+//   {
+//     // user_function's `T` will be deduced to `int` and `Ints...`
+//     // will be deduced to `0, 1, 2, 3, 4`.
+//     user_function(make_integer_sequence<int, 5>());
+//   }
+template <typename T, T... Ints>
+struct integer_sequence
 {
-    if (JSON_UNLIKELY(not j.is_array()))
-    {
-        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
-    }
-    for (const auto& p : j)
+    using value_type = T;
+    static constexpr std::size_t size() noexcept
     {
-        if (JSON_UNLIKELY(not p.is_array()))
-        {
-            JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name())));
-        }
-        m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
+        return sizeof...(Ints);
     }
-}
+};
 
-template <typename BasicJsonType, typename Key, typename Value, typename Hash, typename KeyEqual, typename Allocator,
-          typename = enable_if_t<not std::is_constructible<
-                                     typename BasicJsonType::string_t, Key>::value>>
-void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyEqual, Allocator>& m)
+// index_sequence
+//
+// A helper template for an `integer_sequence` of `size_t`,
+// `absl::index_sequence` is designed to be a drop-in replacement for C++14's
+// `std::index_sequence`.
+template <size_t... Ints>
+using index_sequence = integer_sequence<size_t, Ints...>;
+
+namespace utility_internal
 {
-    if (JSON_UNLIKELY(not j.is_array()))
-    {
-        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
-    }
-    for (const auto& p : j)
-    {
-        if (JSON_UNLIKELY(not p.is_array()))
-        {
-            JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name())));
-        }
-        m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
-    }
-}
 
-struct from_json_fn
+template <typename Seq, size_t SeqSize, size_t Rem>
+struct Extend;
+
+// Note that SeqSize == sizeof...(Ints). It's passed explicitly for efficiency.
+template <typename T, T... Ints, size_t SeqSize>
+struct Extend<integer_sequence<T, Ints...>, SeqSize, 0>
 {
-    template<typename BasicJsonType, typename T>
-    auto operator()(const BasicJsonType& j, T& val) const
-    noexcept(noexcept(from_json(j, val)))
-    -> decltype(from_json(j, val), void())
-    {
-        return from_json(j, val);
-    }
+    using type = integer_sequence < T, Ints..., (Ints + SeqSize)... >;
 };
-}  // namespace detail
 
-/// namespace to hold default `from_json` function
-/// to see why this is required:
-/// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
-namespace
+template <typename T, T... Ints, size_t SeqSize>
+struct Extend<integer_sequence<T, Ints...>, SeqSize, 1>
 {
-constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
-} // namespace
-}  // namespace nlohmann
+    using type = integer_sequence < T, Ints..., (Ints + SeqSize)..., 2 * SeqSize >;
+};
 
-// #include <nlohmann/detail/conversions/to_json.hpp>
+// Recursion helper for 'make_integer_sequence<T, N>'.
+// 'Gen<T, N>::type' is an alias for 'integer_sequence<T, 0, 1, ... N-1>'.
+template <typename T, size_t N>
+struct Gen
+{
+    using type =
+        typename Extend < typename Gen < T, N / 2 >::type, N / 2, N % 2 >::type;
+};
 
+template <typename T>
+struct Gen<T, 0>
+{
+    using type = integer_sequence<T>;
+};
 
-#include <ciso646> // or, and, not
-#include <iterator> // begin, end
-#include <tuple> // tuple, get
-#include <type_traits> // is_same, is_constructible, is_floating_point, is_enum, underlying_type
-#include <utility> // move, forward, declval, pair
-#include <valarray> // valarray
-#include <vector> // vector
+}  // namespace utility_internal
 
-// #include <nlohmann/detail/meta/cpp_future.hpp>
+// Compile-time sequences of integers
 
-// #include <nlohmann/detail/meta/type_traits.hpp>
+// make_integer_sequence
+//
+// This template alias is equivalent to
+// `integer_sequence<int, 0, 1, ..., N-1>`, and is designed to be a drop-in
+// replacement for C++14's `std::make_integer_sequence`.
+template <typename T, T N>
+using make_integer_sequence = typename utility_internal::Gen<T, N>::type;
 
-// #include <nlohmann/detail/value_t.hpp>
+// make_index_sequence
+//
+// This template alias is equivalent to `index_sequence<0, 1, ..., N-1>`,
+// and is designed to be a drop-in replacement for C++14's
+// `std::make_index_sequence`.
+template <size_t N>
+using make_index_sequence = make_integer_sequence<size_t, N>;
 
-// #include <nlohmann/detail/iterators/iteration_proxy.hpp>
+// index_sequence_for
+//
+// Converts a typename pack into an index sequence of the same length, and
+// is designed to be a drop-in replacement for C++14's
+// `std::index_sequence_for()`
+template <typename... Ts>
+using index_sequence_for = make_index_sequence<sizeof...(Ts)>;
 
+//// END OF CODE FROM GOOGLE ABSEIL
 
-#include <cstddef> // size_t
-#include <string> // string, to_string
-#include <iterator> // input_iterator_tag
-#include <tuple> // tuple_size, get, tuple_element
+#endif
 
-// #include <nlohmann/detail/value_t.hpp>
+// dispatch utility (taken from ranges-v3)
+template<unsigned N> struct priority_tag : priority_tag < N - 1 > {};
+template<> struct priority_tag<0> {};
 
-// #include <nlohmann/detail/meta/type_traits.hpp>
+// taken from ranges-v3
+template<typename T>
+struct static_const
+{
+    static constexpr T value{};
+};
+
+template<typename T>
+constexpr T static_const<T>::value;
+
+}  // namespace detail
+}  // namespace nlohmann
+
+// #include <nlohmann/detail/meta/identity_tag.hpp>
 
 
 namespace nlohmann
 {
 namespace detail
 {
-template <typename IteratorType> class iteration_proxy_value
-{
-  public:
-    using difference_type = std::ptrdiff_t;
-    using value_type = iteration_proxy_value;
-    using pointer = value_type * ;
-    using reference = value_type & ;
-    using iterator_category = std::input_iterator_tag;
+// dispatching helper struct
+template <class T> struct identity_tag {};
+}  // namespace detail
+}  // namespace nlohmann
 
-  private:
-    /// the iterator
-    IteratorType anchor;
-    /// an index for arrays (used to create key names)
-    std::size_t array_index = 0;
-    /// last stringified array index
-    mutable std::size_t array_index_last = 0;
-    /// a string representation of the array index
-    mutable std::string array_index_str = "0";
-    /// an empty string (to return a reference for primitive values)
-    const std::string empty_str = "";
+// #include <nlohmann/detail/meta/type_traits.hpp>
 
-  public:
-    explicit iteration_proxy_value(IteratorType it) noexcept : anchor(it) {}
 
-    /// dereference operator (needed for range-based for)
-    iteration_proxy_value& operator*()
-    {
-        return *this;
-    }
+#include <limits> // numeric_limits
+#include <type_traits> // false_type, is_constructible, is_integral, is_same, true_type
+#include <utility> // declval
+#include <tuple> // tuple
 
-    /// increment operator (needed for range-based for)
-    iteration_proxy_value& operator++()
-    {
-        ++anchor;
-        ++array_index;
+// #include <nlohmann/detail/macro_scope.hpp>
 
-        return *this;
-    }
 
-    /// equality operator (needed for InputIterator)
-    bool operator==(const iteration_proxy_value& o) const noexcept
-    {
-        return anchor == o.anchor;
-    }
+// #include <nlohmann/detail/iterators/iterator_traits.hpp>
 
-    /// inequality operator (needed for range-based for)
-    bool operator!=(const iteration_proxy_value& o) const noexcept
-    {
-        return anchor != o.anchor;
-    }
 
-    /// return key of the iterator
-    const std::string& key() const
-    {
-        assert(anchor.m_object != nullptr);
+#include <iterator> // random_access_iterator_tag
 
-        switch (anchor.m_object->type())
-        {
-            // use integer array index as key
-            case value_t::array:
-            {
-                if (array_index != array_index_last)
-                {
-                    array_index_str = std::to_string(array_index);
-                    array_index_last = array_index;
-                }
-                return array_index_str;
-            }
+// #include <nlohmann/detail/meta/void_t.hpp>
 
-            // use key from the object
-            case value_t::object:
-                return anchor.key();
+// #include <nlohmann/detail/meta/cpp_future.hpp>
 
-            // use an empty key for all primitive types
-            default:
-                return empty_str;
-        }
-    }
 
-    /// return value of the iterator
-    typename IteratorType::reference value() const
-    {
-        return anchor.value();
-    }
+namespace nlohmann
+{
+namespace detail
+{
+template<typename It, typename = void>
+struct iterator_types {};
+
+template<typename It>
+struct iterator_types <
+    It,
+    void_t<typename It::difference_type, typename It::value_type, typename It::pointer,
+    typename It::reference, typename It::iterator_category >>
+{
+    using difference_type = typename It::difference_type;
+    using value_type = typename It::value_type;
+    using pointer = typename It::pointer;
+    using reference = typename It::reference;
+    using iterator_category = typename It::iterator_category;
 };
 
-/// proxy class for the items() function
-template<typename IteratorType> class iteration_proxy
+// This is required as some compilers implement std::iterator_traits in a way that
+// doesn't work with SFINAE. See https://github.com/nlohmann/json/issues/1341.
+template<typename T, typename = void>
+struct iterator_traits
 {
-  private:
-    /// the container to iterate
-    typename IteratorType::reference container;
+};
 
-  public:
-    /// construct iteration proxy from a container
-    explicit iteration_proxy(typename IteratorType::reference cont) noexcept
-        : container(cont) {}
+template<typename T>
+struct iterator_traits < T, enable_if_t < !std::is_pointer<T>::value >>
+            : iterator_types<T>
+{
+};
 
-    /// return iterator begin (needed for range-based for)
-    iteration_proxy_value<IteratorType> begin() noexcept
-    {
-        return iteration_proxy_value<IteratorType>(container.begin());
-    }
+template<typename T>
+struct iterator_traits<T*, enable_if_t<std::is_object<T>::value>>
+{
+    using iterator_category = std::random_access_iterator_tag;
+    using value_type = T;
+    using difference_type = ptrdiff_t;
+    using pointer = T*;
+    using reference = T&;
+};
+} // namespace detail
+} // namespace nlohmann
 
-    /// return iterator end (needed for range-based for)
-    iteration_proxy_value<IteratorType> end() noexcept
-    {
-        return iteration_proxy_value<IteratorType>(container.end());
-    }
-};
-// Structured Bindings Support
-// For further reference see https://blog.tartanllama.xyz/structured-bindings/
-// And see https://github.com/nlohmann/json/pull/1391
-template <std::size_t N, typename IteratorType, enable_if_t<N == 0, int> = 0>
-auto get(const nlohmann::detail::iteration_proxy_value<IteratorType>& i) -> decltype(i.key())
-{
-    return i.key();
-}
-// Structured Bindings Support
-// For further reference see https://blog.tartanllama.xyz/structured-bindings/
-// And see https://github.com/nlohmann/json/pull/1391
-template <std::size_t N, typename IteratorType, enable_if_t<N == 1, int> = 0>
-auto get(const nlohmann::detail::iteration_proxy_value<IteratorType>& i) -> decltype(i.value())
-{
-    return i.value();
-}
-}  // namespace detail
-}  // namespace nlohmann
+// #include <nlohmann/detail/meta/call_std/begin.hpp>
 
-// The Addition to the STD Namespace is required to add
-// Structured Bindings Support to the iteration_proxy_value class
-// For further reference see https://blog.tartanllama.xyz/structured-bindings/
-// And see https://github.com/nlohmann/json/pull/1391
-namespace std
-{
-template <typename IteratorType>
-class tuple_size<::nlohmann::detail::iteration_proxy_value<IteratorType>>
-            : public std::integral_constant<std::size_t, 2> {};
 
-template <std::size_t N, typename IteratorType>
-class tuple_element<N, ::nlohmann::detail::iteration_proxy_value<IteratorType >>
-{
-  public:
-    using type = decltype(
-                     get<N>(std::declval <
-                            ::nlohmann::detail::iteration_proxy_value<IteratorType >> ()));
-};
-}
+// #include <nlohmann/detail/macro_scope.hpp>
+
 
 namespace nlohmann
 {
-namespace detail
-{
-//////////////////
-// constructors //
-//////////////////
+NLOHMANN_CAN_CALL_STD_FUNC_IMPL(begin);
+} // namespace nlohmann
 
-template<value_t> struct external_constructor;
+// #include <nlohmann/detail/meta/call_std/end.hpp>
 
-template<>
-struct external_constructor<value_t::boolean>
-{
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept
-    {
-        j.m_type = value_t::boolean;
-        j.m_value = b;
-        j.assert_invariant();
-    }
-};
 
-template<>
-struct external_constructor<value_t::string>
+// #include <nlohmann/detail/macro_scope.hpp>
+
+
+namespace nlohmann
 {
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, const typename BasicJsonType::string_t& s)
-    {
-        j.m_type = value_t::string;
-        j.m_value = s;
-        j.assert_invariant();
-    }
+NLOHMANN_CAN_CALL_STD_FUNC_IMPL(end);
+}  // namespace nlohmann
 
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, typename BasicJsonType::string_t&& s)
-    {
-        j.m_type = value_t::string;
-        j.m_value = std::move(s);
-        j.assert_invariant();
-    }
+// #include <nlohmann/detail/meta/cpp_future.hpp>
 
-    template<typename BasicJsonType, typename CompatibleStringType,
-             enable_if_t<not std::is_same<CompatibleStringType, typename BasicJsonType::string_t>::value,
-                         int> = 0>
-    static void construct(BasicJsonType& j, const CompatibleStringType& str)
-    {
-        j.m_type = value_t::string;
-        j.m_value.string = j.template create<typename BasicJsonType::string_t>(str);
-        j.assert_invariant();
-    }
-};
+// #include <nlohmann/detail/meta/detected.hpp>
 
-template<>
-struct external_constructor<value_t::number_float>
-{
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
-    {
-        j.m_type = value_t::number_float;
-        j.m_value = val;
-        j.assert_invariant();
-    }
-};
+// #include <nlohmann/json_fwd.hpp>
+#ifndef INCLUDE_NLOHMANN_JSON_FWD_HPP_
+#define INCLUDE_NLOHMANN_JSON_FWD_HPP_
 
-template<>
-struct external_constructor<value_t::number_unsigned>
-{
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, typename BasicJsonType::number_unsigned_t val) noexcept
-    {
-        j.m_type = value_t::number_unsigned;
-        j.m_value = val;
-        j.assert_invariant();
-    }
-};
+#include <cstdint> // int64_t, uint64_t
+#include <map> // map
+#include <memory> // allocator
+#include <string> // string
+#include <vector> // vector
 
-template<>
-struct external_constructor<value_t::number_integer>
+/*!
+@brief namespace for Niels Lohmann
+@see https://github.com/nlohmann
+@since version 1.0.0
+*/
+namespace nlohmann
 {
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, typename BasicJsonType::number_integer_t val) noexcept
-    {
-        j.m_type = value_t::number_integer;
-        j.m_value = val;
-        j.assert_invariant();
-    }
-};
+/*!
+@brief default JSONSerializer template argument
 
-template<>
-struct external_constructor<value_t::array>
-{
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, const typename BasicJsonType::array_t& arr)
-    {
-        j.m_type = value_t::array;
-        j.m_value = arr;
-        j.assert_invariant();
-    }
+This serializer ignores the template arguments and uses ADL
+([argument-dependent lookup](https://en.cppreference.com/w/cpp/language/adl))
+for serialization.
+*/
+template<typename T = void, typename SFINAE = void>
+struct adl_serializer;
 
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
-    {
-        j.m_type = value_t::array;
-        j.m_value = std::move(arr);
-        j.assert_invariant();
-    }
+template<template<typename U, typename V, typename... Args> class ObjectType =
+         std::map,
+         template<typename U, typename... Args> class ArrayType = std::vector,
+         class StringType = std::string, class BooleanType = bool,
+         class NumberIntegerType = std::int64_t,
+         class NumberUnsignedType = std::uint64_t,
+         class NumberFloatType = double,
+         template<typename U> class AllocatorType = std::allocator,
+         template<typename T, typename SFINAE = void> class JSONSerializer =
+         adl_serializer,
+         class BinaryType = std::vector<std::uint8_t>>
+class basic_json;
 
-    template<typename BasicJsonType, typename CompatibleArrayType,
-             enable_if_t<not std::is_same<CompatibleArrayType, typename BasicJsonType::array_t>::value,
-                         int> = 0>
-    static void construct(BasicJsonType& j, const CompatibleArrayType& arr)
-    {
-        using std::begin;
-        using std::end;
-        j.m_type = value_t::array;
-        j.m_value.array = j.template create<typename BasicJsonType::array_t>(begin(arr), end(arr));
-        j.assert_invariant();
-    }
+/*!
+@brief JSON Pointer
 
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, const std::vector<bool>& arr)
-    {
-        j.m_type = value_t::array;
-        j.m_value = value_t::array;
-        j.m_value.array->reserve(arr.size());
-        for (const bool x : arr)
-        {
-            j.m_value.array->push_back(x);
-        }
-        j.assert_invariant();
-    }
+A JSON pointer defines a string syntax for identifying a specific value
+within a JSON document. It can be used with functions `at` and
+`operator[]`. Furthermore, JSON pointers are the base for JSON patches.
 
-    template<typename BasicJsonType, typename T,
-             enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
-    static void construct(BasicJsonType& j, const std::valarray<T>& arr)
-    {
-        j.m_type = value_t::array;
-        j.m_value = value_t::array;
-        j.m_value.array->resize(arr.size());
-        std::copy(std::begin(arr), std::end(arr), j.m_value.array->begin());
-        j.assert_invariant();
-    }
-};
+@sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
 
-template<>
-struct external_constructor<value_t::object>
-{
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, const typename BasicJsonType::object_t& obj)
-    {
-        j.m_type = value_t::object;
-        j.m_value = obj;
-        j.assert_invariant();
-    }
+@since version 2.0.0
+*/
+template<typename BasicJsonType>
+class json_pointer;
 
-    template<typename BasicJsonType>
-    static void construct(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
-    {
-        j.m_type = value_t::object;
-        j.m_value = std::move(obj);
-        j.assert_invariant();
-    }
+/*!
+@brief default JSON class
 
-    template<typename BasicJsonType, typename CompatibleObjectType,
-             enable_if_t<not std::is_same<CompatibleObjectType, typename BasicJsonType::object_t>::value, int> = 0>
-    static void construct(BasicJsonType& j, const CompatibleObjectType& obj)
-    {
-        using std::begin;
-        using std::end;
+This type is the default specialization of the @ref basic_json class which
+uses the standard template types.
 
-        j.m_type = value_t::object;
-        j.m_value.object = j.template create<typename BasicJsonType::object_t>(begin(obj), end(obj));
-        j.assert_invariant();
-    }
-};
+@since version 1.0.0
+*/
+using json = basic_json<>;
 
-/////////////
-// to_json //
-/////////////
+template<class Key, class T, class IgnoredLess, class Allocator>
+struct ordered_map;
 
-template<typename BasicJsonType, typename T,
-         enable_if_t<std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
-void to_json(BasicJsonType& j, T b) noexcept
-{
-    external_constructor<value_t::boolean>::construct(j, b);
-}
+/*!
+@brief ordered JSON class
 
-template<typename BasicJsonType, typename CompatibleString,
-         enable_if_t<std::is_constructible<typename BasicJsonType::string_t, CompatibleString>::value, int> = 0>
-void to_json(BasicJsonType& j, const CompatibleString& s)
-{
-    external_constructor<value_t::string>::construct(j, s);
-}
+This type preserves the insertion order of object keys.
 
-template<typename BasicJsonType>
-void to_json(BasicJsonType& j, typename BasicJsonType::string_t&& s)
-{
-    external_constructor<value_t::string>::construct(j, std::move(s));
-}
+@since version 3.9.0
+*/
+using ordered_json = basic_json<nlohmann::ordered_map>;
 
-template<typename BasicJsonType, typename FloatType,
-         enable_if_t<std::is_floating_point<FloatType>::value, int> = 0>
-void to_json(BasicJsonType& j, FloatType val) noexcept
-{
-    external_constructor<value_t::number_float>::construct(j, static_cast<typename BasicJsonType::number_float_t>(val));
-}
+}  // namespace nlohmann
 
-template<typename BasicJsonType, typename CompatibleNumberUnsignedType,
-         enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t, CompatibleNumberUnsignedType>::value, int> = 0>
-void to_json(BasicJsonType& j, CompatibleNumberUnsignedType val) noexcept
-{
-    external_constructor<value_t::number_unsigned>::construct(j, static_cast<typename BasicJsonType::number_unsigned_t>(val));
-}
+#endif  // INCLUDE_NLOHMANN_JSON_FWD_HPP_
 
-template<typename BasicJsonType, typename CompatibleNumberIntegerType,
-         enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t, CompatibleNumberIntegerType>::value, int> = 0>
-void to_json(BasicJsonType& j, CompatibleNumberIntegerType val) noexcept
-{
-    external_constructor<value_t::number_integer>::construct(j, static_cast<typename BasicJsonType::number_integer_t>(val));
-}
 
-template<typename BasicJsonType, typename EnumType,
-         enable_if_t<std::is_enum<EnumType>::value, int> = 0>
-void to_json(BasicJsonType& j, EnumType e) noexcept
+namespace nlohmann
 {
-    using underlying_type = typename std::underlying_type<EnumType>::type;
-    external_constructor<value_t::number_integer>::construct(j, static_cast<underlying_type>(e));
-}
+/*!
+@brief detail namespace with internal helper functions
 
-template<typename BasicJsonType>
-void to_json(BasicJsonType& j, const std::vector<bool>& e)
-{
-    external_constructor<value_t::array>::construct(j, e);
-}
+This namespace collects functions that should not be exposed,
+implementations of some @ref basic_json methods, and meta-programming helpers.
 
-template <typename BasicJsonType, typename CompatibleArrayType,
-          enable_if_t<is_compatible_array_type<BasicJsonType,
-                      CompatibleArrayType>::value and
-                      not is_compatible_object_type<
-                          BasicJsonType, CompatibleArrayType>::value and
-                      not is_compatible_string_type<BasicJsonType, CompatibleArrayType>::value and
-                      not is_basic_json<CompatibleArrayType>::value,
-                      int> = 0>
-void to_json(BasicJsonType& j, const CompatibleArrayType& arr)
+@since version 2.1.0
+*/
+namespace detail
 {
-    external_constructor<value_t::array>::construct(j, arr);
-}
+/////////////
+// helpers //
+/////////////
 
-template<typename BasicJsonType, typename T,
-         enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
-void to_json(BasicJsonType& j, const std::valarray<T>& arr)
-{
-    external_constructor<value_t::array>::construct(j, std::move(arr));
-}
+// Note to maintainers:
+//
+// Every trait in this file expects a non CV-qualified type.
+// The only exceptions are in the 'aliases for detected' section
+// (i.e. those of the form: decltype(T::member_function(std::declval<T>())))
+//
+// In this case, T has to be properly CV-qualified to constraint the function arguments
+// (e.g. to_json(BasicJsonType&, const T&))
 
-template<typename BasicJsonType>
-void to_json(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
-{
-    external_constructor<value_t::array>::construct(j, std::move(arr));
-}
+template<typename> struct is_basic_json : std::false_type {};
 
-template<typename BasicJsonType, typename CompatibleObjectType,
-         enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value and not is_basic_json<CompatibleObjectType>::value, int> = 0>
-void to_json(BasicJsonType& j, const CompatibleObjectType& obj)
-{
-    external_constructor<value_t::object>::construct(j, obj);
-}
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+struct is_basic_json<NLOHMANN_BASIC_JSON_TPL> : std::true_type {};
 
-template<typename BasicJsonType>
-void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
-{
-    external_constructor<value_t::object>::construct(j, std::move(obj));
-}
+//////////////////////
+// json_ref helpers //
+//////////////////////
 
-template <
-    typename BasicJsonType, typename T, std::size_t N,
-    enable_if_t<not std::is_constructible<typename BasicJsonType::string_t,
-                const T(&)[N]>::value,
-                int> = 0 >
-void to_json(BasicJsonType& j, const T(&arr)[N])
-{
-    external_constructor<value_t::array>::construct(j, arr);
-}
+template<typename>
+class json_ref;
 
-template<typename BasicJsonType, typename... Args>
-void to_json(BasicJsonType& j, const std::pair<Args...>& p)
-{
-    j = { p.first, p.second };
-}
+template<typename>
+struct is_json_ref : std::false_type {};
 
-// for https://github.com/nlohmann/json/pull/1134
-template < typename BasicJsonType, typename T,
-           enable_if_t<std::is_same<T, iteration_proxy_value<typename BasicJsonType::iterator>>::value, int> = 0>
-void to_json(BasicJsonType& j, const T& b)
-{
-    j = { {b.key(), b.value()} };
-}
+template<typename T>
+struct is_json_ref<json_ref<T>> : std::true_type {};
 
-template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
-void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<Idx...> /*unused*/)
-{
-    j = { std::get<Idx>(t)... };
-}
+//////////////////////////
+// aliases for detected //
+//////////////////////////
 
-template<typename BasicJsonType, typename... Args>
-void to_json(BasicJsonType& j, const std::tuple<Args...>& t)
-{
-    to_json_tuple_impl(j, t, index_sequence_for<Args...> {});
-}
+template<typename T>
+using mapped_type_t = typename T::mapped_type;
 
-struct to_json_fn
-{
-    template<typename BasicJsonType, typename T>
-    auto operator()(BasicJsonType& j, T&& val) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
-    -> decltype(to_json(j, std::forward<T>(val)), void())
-    {
-        return to_json(j, std::forward<T>(val));
-    }
-};
-}  // namespace detail
+template<typename T>
+using key_type_t = typename T::key_type;
 
-/// namespace to hold default `to_json` function
-namespace
-{
-constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value;
-} // namespace
-}  // namespace nlohmann
+template<typename T>
+using value_type_t = typename T::value_type;
 
-// #include <nlohmann/detail/input/input_adapters.hpp>
+template<typename T>
+using difference_type_t = typename T::difference_type;
 
+template<typename T>
+using pointer_t = typename T::pointer;
 
-#include <cassert> // assert
-#include <cstddef> // size_t
-#include <cstring> // strlen
-#include <istream> // istream
-#include <iterator> // begin, end, iterator_traits, random_access_iterator_tag, distance, next
-#include <memory> // shared_ptr, make_shared, addressof
-#include <numeric> // accumulate
-#include <string> // string, char_traits
-#include <type_traits> // enable_if, is_base_of, is_pointer, is_integral, remove_pointer
-#include <utility> // pair, declval
-#include <cstdio> //FILE *
+template<typename T>
+using reference_t = typename T::reference;
 
-// #include <nlohmann/detail/macro_scope.hpp>
+template<typename T>
+using iterator_category_t = typename T::iterator_category;
 
+template<typename T, typename... Args>
+using to_json_function = decltype(T::to_json(std::declval<Args>()...));
 
-namespace nlohmann
-{
-namespace detail
-{
-/// the supported input formats
-enum class input_format_t { json, cbor, msgpack, ubjson, bson };
+template<typename T, typename... Args>
+using from_json_function = decltype(T::from_json(std::declval<Args>()...));
 
-////////////////////
-// input adapters //
-////////////////////
+template<typename T, typename U>
+using get_template_function = decltype(std::declval<T>().template get<U>());
 
-/*!
-@brief abstract input adapter interface
-
-Produces a stream of std::char_traits<char>::int_type characters from a
-std::istream, a buffer, or some other input type. Accepts the return of
-exactly one non-EOF character for future input. The int_type characters
-returned consist of all valid char values as positive values (typically
-unsigned char), plus an EOF value outside that range, specified by the value
-of the function std::char_traits<char>::eof(). This value is typically -1, but
-could be any arbitrary value which is not a valid char value.
-*/
-struct input_adapter_protocol
+// trait checking if JSONSerializer<T>::from_json(json const&, udt&) exists
+template<typename BasicJsonType, typename T, typename = void>
+struct has_from_json : std::false_type {};
+
+// trait checking if j.get<T> is valid
+// use this trait instead of std::is_constructible or std::is_convertible,
+// both rely on, or make use of implicit conversions, and thus fail when T
+// has several constructors/operator= (see https://github.com/nlohmann/json/issues/958)
+template <typename BasicJsonType, typename T>
+struct is_getable
 {
-    /// get a character [0,255] or std::char_traits<char>::eof().
-    virtual std::char_traits<char>::int_type get_character() = 0;
-    virtual ~input_adapter_protocol() = default;
+    static constexpr bool value = is_detected<get_template_function, const BasicJsonType&, T>::value;
 };
 
-/// a type to simplify interfaces
-using input_adapter_t = std::shared_ptr<input_adapter_protocol>;
-
-/*!
-Input adapter for stdio file access. This adapter read only 1 byte and do not use any
- buffer. This adapter is a very low level adapter.
-*/
-class file_input_adapter : public input_adapter_protocol
+template<typename BasicJsonType, typename T>
+struct has_from_json < BasicJsonType, T, enable_if_t < !is_basic_json<T>::value >>
 {
-  public:
-    explicit file_input_adapter(std::FILE* f)  noexcept
-        : m_file(f)
-    {}
+    using serializer = typename BasicJsonType::template json_serializer<T, void>;
 
-    std::char_traits<char>::int_type get_character() noexcept override
-    {
-        return std::fgetc(m_file);
-    }
-  private:
-    /// the file pointer to read from
-    std::FILE* m_file;
+    static constexpr bool value =
+        is_detected_exact<void, from_json_function, serializer,
+        const BasicJsonType&, T&>::value;
 };
 
+// This trait checks if JSONSerializer<T>::from_json(json const&) exists
+// this overload is used for non-default-constructible user-defined-types
+template<typename BasicJsonType, typename T, typename = void>
+struct has_non_default_from_json : std::false_type {};
 
-/*!
-Input adapter for a (caching) istream. Ignores a UFT Byte Order Mark at
-beginning of input. Does not support changing the underlying std::streambuf
-in mid-input. Maintains underlying std::istream and std::streambuf to support
-subsequent use of standard std::istream operations to process any input
-characters following those used in parsing the JSON input.  Clears the
-std::istream flags; any input errors (e.g., EOF) will be detected by the first
-subsequent call for input from the std::istream.
-*/
-class input_stream_adapter : public input_adapter_protocol
+template<typename BasicJsonType, typename T>
+struct has_non_default_from_json < BasicJsonType, T, enable_if_t < !is_basic_json<T>::value >>
 {
-  public:
-    ~input_stream_adapter() override
-    {
-        // clear stream flags; we use underlying streambuf I/O, do not
-        // maintain ifstream flags, except eof
-        is.clear(is.rdstate() & std::ios::eofbit);
-    }
+    using serializer = typename BasicJsonType::template json_serializer<T, void>;
 
-    explicit input_stream_adapter(std::istream& i)
-        : is(i), sb(*i.rdbuf())
-    {}
+    static constexpr bool value =
+        is_detected_exact<T, from_json_function, serializer,
+        const BasicJsonType&>::value;
+};
 
-    // delete because of pointer members
-    input_stream_adapter(const input_stream_adapter&) = delete;
-    input_stream_adapter& operator=(input_stream_adapter&) = delete;
-    input_stream_adapter(input_stream_adapter&&) = delete;
-    input_stream_adapter& operator=(input_stream_adapter&&) = delete;
+// This trait checks if BasicJsonType::json_serializer<T>::to_json exists
+// Do not evaluate the trait when T is a basic_json type, to avoid template instantiation infinite recursion.
+template<typename BasicJsonType, typename T, typename = void>
+struct has_to_json : std::false_type {};
 
-    // std::istream/std::streambuf use std::char_traits<char>::to_int_type, to
-    // ensure that std::char_traits<char>::eof() and the character 0xFF do not
-    // end up as the same value, eg. 0xFFFFFFFF.
-    std::char_traits<char>::int_type get_character() override
-    {
-        auto res = sb.sbumpc();
-        // set eof manually, as we don't use the istream interface.
-        if (res == EOF)
-        {
-            is.clear(is.rdstate() | std::ios::eofbit);
-        }
-        return res;
-    }
+template<typename BasicJsonType, typename T>
+struct has_to_json < BasicJsonType, T, enable_if_t < !is_basic_json<T>::value >>
+{
+    using serializer = typename BasicJsonType::template json_serializer<T, void>;
 
-  private:
-    /// the associated input stream
-    std::istream& is;
-    std::streambuf& sb;
+    static constexpr bool value =
+        is_detected_exact<void, to_json_function, serializer, BasicJsonType&,
+        T>::value;
 };
 
-/// input adapter for buffer input
-class input_buffer_adapter : public input_adapter_protocol
-{
-  public:
-    input_buffer_adapter(const char* b, const std::size_t l) noexcept
-        : cursor(b), limit(b + l)
-    {}
 
-    // delete because of pointer members
-    input_buffer_adapter(const input_buffer_adapter&) = delete;
-    input_buffer_adapter& operator=(input_buffer_adapter&) = delete;
-    input_buffer_adapter(input_buffer_adapter&&) = delete;
-    input_buffer_adapter& operator=(input_buffer_adapter&&) = delete;
-    ~input_buffer_adapter() override = default;
+///////////////////
+// is_ functions //
+///////////////////
 
-    std::char_traits<char>::int_type get_character() noexcept override
-    {
-        if (JSON_LIKELY(cursor < limit))
-        {
-            return std::char_traits<char>::to_int_type(*(cursor++));
-        }
+// https://en.cppreference.com/w/cpp/types/conjunction
+template<class...> struct conjunction : std::true_type { };
+template<class B1> struct conjunction<B1> : B1 { };
+template<class B1, class... Bn>
+struct conjunction<B1, Bn...>
+: std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
 
-        return std::char_traits<char>::eof();
-    }
+// https://en.cppreference.com/w/cpp/types/negation
+template<class B> struct negation : std::integral_constant < bool, !B::value > { };
 
-  private:
-    /// pointer to the current character
-    const char* cursor;
-    /// pointer past the last character
-    const char* const limit;
-};
+// Reimplementation of is_constructible and is_default_constructible, due to them being broken for
+// std::pair and std::tuple until LWG 2367 fix (see https://cplusplus.github.io/LWG/lwg-defects.html#2367).
+// This causes compile errors in e.g. clang 3.5 or gcc 4.9.
+template <typename T>
+struct is_default_constructible : std::is_default_constructible<T> {};
 
-template<typename WideStringType, size_t T>
-struct wide_string_input_helper
-{
-    // UTF-32
-    static void fill_buffer(const WideStringType& str, size_t& current_wchar, std::array<std::char_traits<char>::int_type, 4>& utf8_bytes, size_t& utf8_bytes_index, size_t& utf8_bytes_filled)
-    {
-        utf8_bytes_index = 0;
+template <typename T1, typename T2>
+struct is_default_constructible<std::pair<T1, T2>>
+            : conjunction<is_default_constructible<T1>, is_default_constructible<T2>> {};
 
-        if (current_wchar == str.size())
-        {
-            utf8_bytes[0] = std::char_traits<char>::eof();
-            utf8_bytes_filled = 1;
-        }
-        else
-        {
-            // get the current character
-            const auto wc = static_cast<int>(str[current_wchar++]);
+template <typename T1, typename T2>
+struct is_default_constructible<const std::pair<T1, T2>>
+            : conjunction<is_default_constructible<T1>, is_default_constructible<T2>> {};
 
-            // UTF-32 to UTF-8 encoding
-            if (wc < 0x80)
-            {
-                utf8_bytes[0] = wc;
-                utf8_bytes_filled = 1;
-            }
-            else if (wc <= 0x7FF)
-            {
-                utf8_bytes[0] = 0xC0 | ((wc >> 6) & 0x1F);
-                utf8_bytes[1] = 0x80 | (wc & 0x3F);
-                utf8_bytes_filled = 2;
-            }
-            else if (wc <= 0xFFFF)
-            {
-                utf8_bytes[0] = 0xE0 | ((wc >> 12) & 0x0F);
-                utf8_bytes[1] = 0x80 | ((wc >> 6) & 0x3F);
-                utf8_bytes[2] = 0x80 | (wc & 0x3F);
-                utf8_bytes_filled = 3;
-            }
-            else if (wc <= 0x10FFFF)
-            {
-                utf8_bytes[0] = 0xF0 | ((wc >> 18) & 0x07);
-                utf8_bytes[1] = 0x80 | ((wc >> 12) & 0x3F);
-                utf8_bytes[2] = 0x80 | ((wc >> 6) & 0x3F);
-                utf8_bytes[3] = 0x80 | (wc & 0x3F);
-                utf8_bytes_filled = 4;
-            }
-            else
-            {
-                // unknown character
-                utf8_bytes[0] = wc;
-                utf8_bytes_filled = 1;
-            }
-        }
-    }
+template <typename... Ts>
+struct is_default_constructible<std::tuple<Ts...>>
+            : conjunction<is_default_constructible<Ts>...> {};
+
+template <typename... Ts>
+struct is_default_constructible<const std::tuple<Ts...>>
+            : conjunction<is_default_constructible<Ts>...> {};
+
+
+template <typename T, typename... Args>
+struct is_constructible : std::is_constructible<T, Args...> {};
+
+template <typename T1, typename T2>
+struct is_constructible<std::pair<T1, T2>> : is_default_constructible<std::pair<T1, T2>> {};
+
+template <typename T1, typename T2>
+struct is_constructible<const std::pair<T1, T2>> : is_default_constructible<const std::pair<T1, T2>> {};
+
+template <typename... Ts>
+struct is_constructible<std::tuple<Ts...>> : is_default_constructible<std::tuple<Ts...>> {};
+
+template <typename... Ts>
+struct is_constructible<const std::tuple<Ts...>> : is_default_constructible<const std::tuple<Ts...>> {};
+
+
+template<typename T, typename = void>
+struct is_iterator_traits : std::false_type {};
+
+template<typename T>
+struct is_iterator_traits<iterator_traits<T>>
+{
+  private:
+    using traits = iterator_traits<T>;
+
+  public:
+    static constexpr auto value =
+        is_detected<value_type_t, traits>::value &&
+        is_detected<difference_type_t, traits>::value &&
+        is_detected<pointer_t, traits>::value &&
+        is_detected<iterator_category_t, traits>::value &&
+        is_detected<reference_t, traits>::value;
 };
 
-template<typename WideStringType>
-struct wide_string_input_helper<WideStringType, 2>
+template<typename T>
+struct is_range
 {
-    // UTF-16
-    static void fill_buffer(const WideStringType& str, size_t& current_wchar, std::array<std::char_traits<char>::int_type, 4>& utf8_bytes, size_t& utf8_bytes_index, size_t& utf8_bytes_filled)
-    {
-        utf8_bytes_index = 0;
+  private:
+    using t_ref = typename std::add_lvalue_reference<T>::type;
 
-        if (current_wchar == str.size())
-        {
-            utf8_bytes[0] = std::char_traits<char>::eof();
-            utf8_bytes_filled = 1;
-        }
-        else
-        {
-            // get the current character
-            const auto wc = static_cast<int>(str[current_wchar++]);
+    using iterator = detected_t<result_of_begin, t_ref>;
+    using sentinel = detected_t<result_of_end, t_ref>;
 
-            // UTF-16 to UTF-8 encoding
-            if (wc < 0x80)
-            {
-                utf8_bytes[0] = wc;
-                utf8_bytes_filled = 1;
-            }
-            else if (wc <= 0x7FF)
-            {
-                utf8_bytes[0] = 0xC0 | ((wc >> 6));
-                utf8_bytes[1] = 0x80 | (wc & 0x3F);
-                utf8_bytes_filled = 2;
-            }
-            else if (0xD800 > wc or wc >= 0xE000)
-            {
-                utf8_bytes[0] = 0xE0 | ((wc >> 12));
-                utf8_bytes[1] = 0x80 | ((wc >> 6) & 0x3F);
-                utf8_bytes[2] = 0x80 | (wc & 0x3F);
-                utf8_bytes_filled = 3;
-            }
-            else
-            {
-                if (current_wchar < str.size())
-                {
-                    const auto wc2 = static_cast<int>(str[current_wchar++]);
-                    const int charcode = 0x10000 + (((wc & 0x3FF) << 10) | (wc2 & 0x3FF));
-                    utf8_bytes[0] = 0xf0 | (charcode >> 18);
-                    utf8_bytes[1] = 0x80 | ((charcode >> 12) & 0x3F);
-                    utf8_bytes[2] = 0x80 | ((charcode >> 6) & 0x3F);
-                    utf8_bytes[3] = 0x80 | (charcode & 0x3F);
-                    utf8_bytes_filled = 4;
-                }
-                else
-                {
-                    // unknown character
-                    ++current_wchar;
-                    utf8_bytes[0] = wc;
-                    utf8_bytes_filled = 1;
-                }
-            }
-        }
-    }
+    // to be 100% correct, it should use https://en.cppreference.com/w/cpp/iterator/input_or_output_iterator
+    // and https://en.cppreference.com/w/cpp/iterator/sentinel_for
+    // but reimplementing these would be too much work, as a lot of other concepts are used underneath
+    static constexpr auto is_iterator_begin =
+        is_iterator_traits<iterator_traits<iterator>>::value;
+
+  public:
+    static constexpr bool value = !std::is_same<iterator, nonesuch>::value && !std::is_same<sentinel, nonesuch>::value && is_iterator_begin;
 };
 
-template<typename WideStringType>
-class wide_string_input_adapter : public input_adapter_protocol
+template<typename R>
+using iterator_t = enable_if_t<is_range<R>::value, result_of_begin<decltype(std::declval<R&>())>>;
+
+template<typename T>
+using range_value_t = value_type_t<iterator_traits<iterator_t<T>>>;
+
+// The following implementation of is_complete_type is taken from
+// https://blogs.msdn.microsoft.com/vcblog/2015/12/02/partial-support-for-expression-sfinae-in-vs-2015-update-1/
+// and is written by Xiang Fan who agreed to using it in this library.
+
+template<typename T, typename = void>
+struct is_complete_type : std::false_type {};
+
+template<typename T>
+struct is_complete_type<T, decltype(void(sizeof(T)))> : std::true_type {};
+
+template<typename BasicJsonType, typename CompatibleObjectType,
+         typename = void>
+struct is_compatible_object_type_impl : std::false_type {};
+
+template<typename BasicJsonType, typename CompatibleObjectType>
+struct is_compatible_object_type_impl <
+    BasicJsonType, CompatibleObjectType,
+    enable_if_t < is_detected<mapped_type_t, CompatibleObjectType>::value&&
+    is_detected<key_type_t, CompatibleObjectType>::value >>
 {
-  public:
-    explicit wide_string_input_adapter(const WideStringType& w)  noexcept
-        : str(w)
-    {}
+    using object_t = typename BasicJsonType::object_t;
 
-    std::char_traits<char>::int_type get_character() noexcept override
-    {
-        // check if buffer needs to be filled
-        if (utf8_bytes_index == utf8_bytes_filled)
-        {
-            fill_buffer<sizeof(typename WideStringType::value_type)>();
+    // macOS's is_constructible does not play well with nonesuch...
+    static constexpr bool value =
+        is_constructible<typename object_t::key_type,
+        typename CompatibleObjectType::key_type>::value &&
+        is_constructible<typename object_t::mapped_type,
+        typename CompatibleObjectType::mapped_type>::value;
+};
 
-            assert(utf8_bytes_filled > 0);
-            assert(utf8_bytes_index == 0);
-        }
+template<typename BasicJsonType, typename CompatibleObjectType>
+struct is_compatible_object_type
+    : is_compatible_object_type_impl<BasicJsonType, CompatibleObjectType> {};
 
-        // use buffer
-        assert(utf8_bytes_filled > 0);
-        assert(utf8_bytes_index < utf8_bytes_filled);
-        return utf8_bytes[utf8_bytes_index++];
-    }
+template<typename BasicJsonType, typename ConstructibleObjectType,
+         typename = void>
+struct is_constructible_object_type_impl : std::false_type {};
 
-  private:
-    template<size_t T>
-    void fill_buffer()
-    {
-        wide_string_input_helper<WideStringType, T>::fill_buffer(str, current_wchar, utf8_bytes, utf8_bytes_index, utf8_bytes_filled);
-    }
+template<typename BasicJsonType, typename ConstructibleObjectType>
+struct is_constructible_object_type_impl <
+    BasicJsonType, ConstructibleObjectType,
+    enable_if_t < is_detected<mapped_type_t, ConstructibleObjectType>::value&&
+    is_detected<key_type_t, ConstructibleObjectType>::value >>
+{
+    using object_t = typename BasicJsonType::object_t;
 
-    /// the wstring to process
-    const WideStringType& str;
+    static constexpr bool value =
+        (is_default_constructible<ConstructibleObjectType>::value &&
+         (std::is_move_assignable<ConstructibleObjectType>::value ||
+          std::is_copy_assignable<ConstructibleObjectType>::value) &&
+         (is_constructible<typename ConstructibleObjectType::key_type,
+          typename object_t::key_type>::value &&
+          std::is_same <
+          typename object_t::mapped_type,
+          typename ConstructibleObjectType::mapped_type >::value)) ||
+        (has_from_json<BasicJsonType,
+         typename ConstructibleObjectType::mapped_type>::value ||
+         has_non_default_from_json <
+         BasicJsonType,
+         typename ConstructibleObjectType::mapped_type >::value);
+};
 
-    /// index of the current wchar in str
-    std::size_t current_wchar = 0;
+template<typename BasicJsonType, typename ConstructibleObjectType>
+struct is_constructible_object_type
+    : is_constructible_object_type_impl<BasicJsonType,
+      ConstructibleObjectType> {};
 
-    /// a buffer for UTF-8 bytes
-    std::array<std::char_traits<char>::int_type, 4> utf8_bytes = {{0, 0, 0, 0}};
+template<typename BasicJsonType, typename CompatibleStringType>
+struct is_compatible_string_type
+{
+    static constexpr auto value =
+        is_constructible<typename BasicJsonType::string_t, CompatibleStringType>::value;
+};
 
-    /// index to the utf8_codes array for the next valid byte
-    std::size_t utf8_bytes_index = 0;
-    /// number of valid bytes in the utf8_codes array
-    std::size_t utf8_bytes_filled = 0;
+template<typename BasicJsonType, typename ConstructibleStringType>
+struct is_constructible_string_type
+{
+    static constexpr auto value =
+        is_constructible<ConstructibleStringType,
+        typename BasicJsonType::string_t>::value;
 };
 
-class input_adapter
+template<typename BasicJsonType, typename CompatibleArrayType, typename = void>
+struct is_compatible_array_type_impl : std::false_type {};
+
+template<typename BasicJsonType, typename CompatibleArrayType>
+struct is_compatible_array_type_impl <
+    BasicJsonType, CompatibleArrayType,
+    enable_if_t <
+    is_detected<iterator_t, CompatibleArrayType>::value&&
+    is_iterator_traits<iterator_traits<detected_t<iterator_t, CompatibleArrayType>>>::value&&
+// special case for types like std::filesystem::path whose iterator's value_type are themselves
+// c.f. https://github.com/nlohmann/json/pull/3073
+    !std::is_same<CompatibleArrayType, detected_t<range_value_t, CompatibleArrayType>>::value >>
 {
-  public:
-    // native support
-    input_adapter(std::FILE* file)
-        : ia(std::make_shared<file_input_adapter>(file)) {}
-    /// input adapter for input stream
-    input_adapter(std::istream& i)
-        : ia(std::make_shared<input_stream_adapter>(i)) {}
+    static constexpr bool value =
+        is_constructible<BasicJsonType,
+        range_value_t<CompatibleArrayType>>::value;
+};
 
-    /// input adapter for input stream
-    input_adapter(std::istream&& i)
-        : ia(std::make_shared<input_stream_adapter>(i)) {}
+template<typename BasicJsonType, typename CompatibleArrayType>
+struct is_compatible_array_type
+    : is_compatible_array_type_impl<BasicJsonType, CompatibleArrayType> {};
 
-    input_adapter(const std::wstring& ws)
-        : ia(std::make_shared<wide_string_input_adapter<std::wstring>>(ws)) {}
+template<typename BasicJsonType, typename ConstructibleArrayType, typename = void>
+struct is_constructible_array_type_impl : std::false_type {};
 
-    input_adapter(const std::u16string& ws)
-        : ia(std::make_shared<wide_string_input_adapter<std::u16string>>(ws)) {}
+template<typename BasicJsonType, typename ConstructibleArrayType>
+struct is_constructible_array_type_impl <
+    BasicJsonType, ConstructibleArrayType,
+    enable_if_t<std::is_same<ConstructibleArrayType,
+    typename BasicJsonType::value_type>::value >>
+            : std::true_type {};
 
-    input_adapter(const std::u32string& ws)
-        : ia(std::make_shared<wide_string_input_adapter<std::u32string>>(ws)) {}
+template<typename BasicJsonType, typename ConstructibleArrayType>
+struct is_constructible_array_type_impl <
+    BasicJsonType, ConstructibleArrayType,
+    enable_if_t < !std::is_same<ConstructibleArrayType,
+    typename BasicJsonType::value_type>::value&&
+    !is_compatible_string_type<BasicJsonType, ConstructibleArrayType>::value&&
+    is_default_constructible<ConstructibleArrayType>::value&&
+(std::is_move_assignable<ConstructibleArrayType>::value ||
+ std::is_copy_assignable<ConstructibleArrayType>::value)&&
+is_detected<iterator_t, ConstructibleArrayType>::value&&
+is_iterator_traits<iterator_traits<detected_t<iterator_t, ConstructibleArrayType>>>::value&&
+is_detected<range_value_t, ConstructibleArrayType>::value&&
+// special case for types like std::filesystem::path whose iterator's value_type are themselves
+// c.f. https://github.com/nlohmann/json/pull/3073
+!std::is_same<ConstructibleArrayType, detected_t<range_value_t, ConstructibleArrayType>>::value&&
+        is_complete_type <
+        detected_t<range_value_t, ConstructibleArrayType >>::value >>
+{
+    using value_type = range_value_t<ConstructibleArrayType>;
 
-    /// input adapter for buffer
-    template<typename CharT,
-             typename std::enable_if<
-                 std::is_pointer<CharT>::value and
-                 std::is_integral<typename std::remove_pointer<CharT>::type>::value and
-                 sizeof(typename std::remove_pointer<CharT>::type) == 1,
-                 int>::type = 0>
-    input_adapter(CharT b, std::size_t l)
-        : ia(std::make_shared<input_buffer_adapter>(reinterpret_cast<const char*>(b), l)) {}
+    static constexpr bool value =
+        std::is_same<value_type,
+        typename BasicJsonType::array_t::value_type>::value ||
+        has_from_json<BasicJsonType,
+        value_type>::value ||
+        has_non_default_from_json <
+        BasicJsonType,
+        value_type >::value;
+};
 
-    // derived support
+template<typename BasicJsonType, typename ConstructibleArrayType>
+struct is_constructible_array_type
+    : is_constructible_array_type_impl<BasicJsonType, ConstructibleArrayType> {};
 
-    /// input adapter for string literal
-    template<typename CharT,
-             typename std::enable_if<
-                 std::is_pointer<CharT>::value and
-                 std::is_integral<typename std::remove_pointer<CharT>::type>::value and
-                 sizeof(typename std::remove_pointer<CharT>::type) == 1,
-                 int>::type = 0>
-    input_adapter(CharT b)
-        : input_adapter(reinterpret_cast<const char*>(b),
-                        std::strlen(reinterpret_cast<const char*>(b))) {}
+template<typename RealIntegerType, typename CompatibleNumberIntegerType,
+         typename = void>
+struct is_compatible_integer_type_impl : std::false_type {};
 
-    /// input adapter for iterator range with contiguous storage
-    template<class IteratorType,
-             typename std::enable_if<
-                 std::is_same<typename iterator_traits<IteratorType>::iterator_category, std::random_access_iterator_tag>::value,
-                 int>::type = 0>
-    input_adapter(IteratorType first, IteratorType last)
-    {
-#ifndef NDEBUG
-        // assertion to check that the iterator range is indeed contiguous,
-        // see http://stackoverflow.com/a/35008842/266378 for more discussion
-        const auto is_contiguous = std::accumulate(
-                                       first, last, std::pair<bool, int>(true, 0),
-                                       [&first](std::pair<bool, int> res, decltype(*first) val)
-        {
-            res.first &= (val == *(std::next(std::addressof(*first), res.second++)));
-            return res;
-        }).first;
-        assert(is_contiguous);
-#endif
+template<typename RealIntegerType, typename CompatibleNumberIntegerType>
+struct is_compatible_integer_type_impl <
+    RealIntegerType, CompatibleNumberIntegerType,
+    enable_if_t < std::is_integral<RealIntegerType>::value&&
+    std::is_integral<CompatibleNumberIntegerType>::value&&
+    !std::is_same<bool, CompatibleNumberIntegerType>::value >>
+{
+    // is there an assert somewhere on overflows?
+    using RealLimits = std::numeric_limits<RealIntegerType>;
+    using CompatibleLimits = std::numeric_limits<CompatibleNumberIntegerType>;
 
-        // assertion to check that each element is 1 byte long
-        static_assert(
-            sizeof(typename iterator_traits<IteratorType>::value_type) == 1,
-            "each element in the iterator range must have the size of 1 byte");
+    static constexpr auto value =
+        is_constructible<RealIntegerType,
+        CompatibleNumberIntegerType>::value &&
+        CompatibleLimits::is_integer &&
+        RealLimits::is_signed == CompatibleLimits::is_signed;
+};
 
-        const auto len = static_cast<size_t>(std::distance(first, last));
-        if (JSON_LIKELY(len > 0))
-        {
-            // there is at least one element: use the address of first
-            ia = std::make_shared<input_buffer_adapter>(reinterpret_cast<const char*>(&(*first)), len);
-        }
-        else
-        {
-            // the address of first cannot be used: use nullptr
-            ia = std::make_shared<input_buffer_adapter>(nullptr, len);
-        }
-    }
+template<typename RealIntegerType, typename CompatibleNumberIntegerType>
+struct is_compatible_integer_type
+    : is_compatible_integer_type_impl<RealIntegerType,
+      CompatibleNumberIntegerType> {};
+
+template<typename BasicJsonType, typename CompatibleType, typename = void>
+struct is_compatible_type_impl: std::false_type {};
+
+template<typename BasicJsonType, typename CompatibleType>
+struct is_compatible_type_impl <
+    BasicJsonType, CompatibleType,
+    enable_if_t<is_complete_type<CompatibleType>::value >>
+{
+    static constexpr bool value =
+        has_to_json<BasicJsonType, CompatibleType>::value;
+};
+
+template<typename BasicJsonType, typename CompatibleType>
+struct is_compatible_type
+    : is_compatible_type_impl<BasicJsonType, CompatibleType> {};
 
-    /// input adapter for array
-    template<class T, std::size_t N>
-    input_adapter(T (&array)[N])
-        : input_adapter(std::begin(array), std::end(array)) {}
+template<typename T1, typename T2>
+struct is_constructible_tuple : std::false_type {};
 
-    /// input adapter for contiguous container
-    template<class ContiguousContainer, typename
-             std::enable_if<not std::is_pointer<ContiguousContainer>::value and
-                            std::is_base_of<std::random_access_iterator_tag, typename iterator_traits<decltype(std::begin(std::declval<ContiguousContainer const>()))>::iterator_category>::value,
-                            int>::type = 0>
-    input_adapter(const ContiguousContainer& c)
-        : input_adapter(std::begin(c), std::end(c)) {}
+template<typename T1, typename... Args>
+struct is_constructible_tuple<T1, std::tuple<Args...>> : conjunction<is_constructible<T1, Args>...> {};
 
-    operator input_adapter_t()
+// a naive helper to check if a type is an ordered_map (exploits the fact that
+// ordered_map inherits capacity() from std::vector)
+template <typename T>
+struct is_ordered_map
+{
+    using one = char;
+
+    struct two
     {
-        return ia;
-    }
+        char x[2]; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+    };
 
-  private:
-    /// the actual adapter
-    input_adapter_t ia = nullptr;
-};
-}  // namespace detail
-}  // namespace nlohmann
+    template <typename C> static one test( decltype(&C::capacity) ) ;
+    template <typename C> static two test(...);
 
-// #include <nlohmann/detail/input/lexer.hpp>
+    enum { value = sizeof(test<T>(nullptr)) == sizeof(char) }; // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+};
 
+// to avoid useless casts (see https://github.com/nlohmann/json/issues/2893#issuecomment-889152324)
+template < typename T, typename U, enable_if_t < !std::is_same<T, U>::value, int > = 0 >
+T conditional_static_cast(U value)
+{
+    return static_cast<T>(value);
+}
 
-#include <clocale> // localeconv
-#include <cstddef> // size_t
-#include <cstdlib> // strtof, strtod, strtold, strtoll, strtoull
-#include <cstdio> // snprintf
-#include <initializer_list> // initializer_list
-#include <string> // char_traits, string
-#include <vector> // vector
+template<typename T, typename U, enable_if_t<std::is_same<T, U>::value, int> = 0>
+T conditional_static_cast(U value)
+{
+    return value;
+}
 
-// #include <nlohmann/detail/macro_scope.hpp>
+}  // namespace detail
+}  // namespace nlohmann
 
-// #include <nlohmann/detail/input/input_adapters.hpp>
+// #include <nlohmann/detail/value_t.hpp>
 
-// #include <nlohmann/detail/input/position_t.hpp>
 
+#ifdef JSON_HAS_CPP_17
+    #include <filesystem>
+#endif
 
 namespace nlohmann
 {
 namespace detail
 {
-///////////
-// lexer //
-///////////
-
-/*!
-@brief lexical analysis
-
-This class organizes the lexical analysis during JSON deserialization.
-*/
 template<typename BasicJsonType>
-class lexer
+void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
 {
-    using number_integer_t = typename BasicJsonType::number_integer_t;
-    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-    using number_float_t = typename BasicJsonType::number_float_t;
-    using string_t = typename BasicJsonType::string_t;
-
-  public:
-    /// token types for the parser
-    enum class token_type
+    if (JSON_HEDLEY_UNLIKELY(!j.is_null()))
     {
-        uninitialized,    ///< indicating the scanner is uninitialized
-        literal_true,     ///< the `true` literal
-        literal_false,    ///< the `false` literal
-        literal_null,     ///< the `null` literal
-        value_string,     ///< a string -- use get_string() for actual value
-        value_unsigned,   ///< an unsigned integer -- use get_number_unsigned() for actual value
-        value_integer,    ///< a signed integer -- use get_number_integer() for actual value
-        value_float,      ///< an floating point number -- use get_number_float() for actual value
-        begin_array,      ///< the character for array begin `[`
-        begin_object,     ///< the character for object begin `{`
-        end_array,        ///< the character for array end `]`
-        end_object,       ///< the character for object end `}`
-        name_separator,   ///< the name separator `:`
-        value_separator,  ///< the value separator `,`
-        parse_error,      ///< indicating a parse error
-        end_of_input,     ///< indicating the end of the input buffer
-        literal_or_value  ///< a literal or the begin of a value (only for diagnostics)
-    };
+        JSON_THROW(type_error::create(302, "type must be null, but is " + std::string(j.type_name()), j));
+    }
+    n = nullptr;
+}
 
-    /// return name of values of type token_type (only used for errors)
-    static const char* token_type_name(const token_type t) noexcept
+// overloads for basic_json template parameters
+template < typename BasicJsonType, typename ArithmeticType,
+           enable_if_t < std::is_arithmetic<ArithmeticType>::value&&
+                         !std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
+                         int > = 0 >
+void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
+{
+    switch (static_cast<value_t>(j))
     {
-        switch (t)
+        case value_t::number_unsigned:
         {
-            case token_type::uninitialized:
-                return "<uninitialized>";
-            case token_type::literal_true:
-                return "true literal";
-            case token_type::literal_false:
-                return "false literal";
-            case token_type::literal_null:
-                return "null literal";
-            case token_type::value_string:
-                return "string literal";
-            case lexer::token_type::value_unsigned:
-            case lexer::token_type::value_integer:
-            case lexer::token_type::value_float:
-                return "number literal";
-            case token_type::begin_array:
-                return "'['";
-            case token_type::begin_object:
-                return "'{'";
-            case token_type::end_array:
-                return "']'";
-            case token_type::end_object:
-                return "'}'";
-            case token_type::name_separator:
-                return "':'";
-            case token_type::value_separator:
-                return "','";
-            case token_type::parse_error:
-                return "<parse error>";
-            case token_type::end_of_input:
-                return "end of input";
-            case token_type::literal_or_value:
-                return "'[', '{', or a literal";
-            // LCOV_EXCL_START
-            default: // catch non-enum values
-                return "unknown token";
-                // LCOV_EXCL_STOP
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
+            break;
+        }
+        case value_t::number_integer:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
+            break;
+        }
+        case value_t::number_float:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
+            break;
         }
-    }
-
-    explicit lexer(detail::input_adapter_t&& adapter)
-        : ia(std::move(adapter)), decimal_point_char(get_decimal_point()) {}
 
-    // delete because of pointer members
-    lexer(const lexer&) = delete;
-    lexer(lexer&&) = delete;
-    lexer& operator=(lexer&) = delete;
-    lexer& operator=(lexer&&) = delete;
-    ~lexer() = default;
+        case value_t::null:
+        case value_t::object:
+        case value_t::array:
+        case value_t::string:
+        case value_t::boolean:
+        case value_t::binary:
+        case value_t::discarded:
+        default:
+            JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name()), j));
+    }
+}
 
-  private:
-    /////////////////////
-    // locales
-    /////////////////////
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_boolean()))
+    {
+        JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(j.type_name()), j));
+    }
+    b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
+}
 
-    /// return the locale-dependent decimal point
-    static char get_decimal_point() noexcept
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_string()))
     {
-        const auto loc = localeconv();
-        assert(loc != nullptr);
-        return (loc->decimal_point == nullptr) ? '.' : *(loc->decimal_point);
+        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name()), j));
     }
+    s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
+}
 
-    /////////////////////
-    // scan functions
-    /////////////////////
+template <
+    typename BasicJsonType, typename ConstructibleStringType,
+    enable_if_t <
+        is_constructible_string_type<BasicJsonType, ConstructibleStringType>::value&&
+        !std::is_same<typename BasicJsonType::string_t,
+                      ConstructibleStringType>::value,
+        int > = 0 >
+void from_json(const BasicJsonType& j, ConstructibleStringType& s)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_string()))
+    {
+        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name()), j));
+    }
 
-    /*!
-    @brief get codepoint from 4 hex characters following `\u`
+    s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
+}
 
-    For input "\u c1 c2 c3 c4" the codepoint is:
-      (c1 * 0x1000) + (c2 * 0x0100) + (c3 * 0x0010) + c4
-    = (c1 << 12) + (c2 << 8) + (c3 << 4) + (c4 << 0)
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::number_float_t& val)
+{
+    get_arithmetic_value(j, val);
+}
 
-    Furthermore, the possible characters '0'..'9', 'A'..'F', and 'a'..'f'
-    must be converted to the integers 0x0..0x9, 0xA..0xF, 0xA..0xF, resp. The
-    conversion is done by subtracting the offset (0x30, 0x37, and 0x57)
-    between the ASCII value of the character and the desired integer value.
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val)
+{
+    get_arithmetic_value(j, val);
+}
 
-    @return codepoint (0x0000..0xFFFF) or -1 in case of an error (e.g. EOF or
-            non-hex character)
-    */
-    int get_codepoint()
-    {
-        // this function only makes sense after reading `\u`
-        assert(current == 'u');
-        int codepoint = 0;
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::number_integer_t& val)
+{
+    get_arithmetic_value(j, val);
+}
 
-        const auto factors = { 12, 8, 4, 0 };
-        for (const auto factor : factors)
-        {
-            get();
+template<typename BasicJsonType, typename EnumType,
+         enable_if_t<std::is_enum<EnumType>::value, int> = 0>
+void from_json(const BasicJsonType& j, EnumType& e)
+{
+    typename std::underlying_type<EnumType>::type val;
+    get_arithmetic_value(j, val);
+    e = static_cast<EnumType>(val);
+}
 
-            if (current >= '0' and current <= '9')
-            {
-                codepoint += ((current - 0x30) << factor);
-            }
-            else if (current >= 'A' and current <= 'F')
-            {
-                codepoint += ((current - 0x37) << factor);
-            }
-            else if (current >= 'a' and current <= 'f')
-            {
-                codepoint += ((current - 0x57) << factor);
-            }
-            else
-            {
-                return -1;
-            }
-        }
+// forward_list doesn't have an insert method
+template<typename BasicJsonType, typename T, typename Allocator,
+         enable_if_t<is_getable<BasicJsonType, T>::value, int> = 0>
+void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
+    }
+    l.clear();
+    std::transform(j.rbegin(), j.rend(),
+                   std::front_inserter(l), [](const BasicJsonType & i)
+    {
+        return i.template get<T>();
+    });
+}
 
-        assert(0x0000 <= codepoint and codepoint <= 0xFFFF);
-        return codepoint;
+// valarray doesn't have an insert method
+template<typename BasicJsonType, typename T,
+         enable_if_t<is_getable<BasicJsonType, T>::value, int> = 0>
+void from_json(const BasicJsonType& j, std::valarray<T>& l)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
     }
+    l.resize(j.size());
+    std::transform(j.begin(), j.end(), std::begin(l),
+                   [](const BasicJsonType & elem)
+    {
+        return elem.template get<T>();
+    });
+}
 
-    /*!
-    @brief check if the next byte(s) are inside a given range
+template<typename BasicJsonType, typename T, std::size_t N>
+auto from_json(const BasicJsonType& j, T (&arr)[N])  // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+-> decltype(j.template get<T>(), void())
+{
+    for (std::size_t i = 0; i < N; ++i)
+    {
+        arr[i] = j.at(i).template get<T>();
+    }
+}
 
-    Adds the current byte and, for each passed range, reads a new byte and
-    checks if it is inside the range. If a violation was detected, set up an
-    error message and return false. Otherwise, return true.
+template<typename BasicJsonType>
+void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType::array_t& arr, priority_tag<3> /*unused*/)
+{
+    arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
+}
 
-    @param[in] ranges  list of integers; interpreted as list of pairs of
-                       inclusive lower and upper bound, respectively
+template<typename BasicJsonType, typename T, std::size_t N>
+auto from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr,
+                          priority_tag<2> /*unused*/)
+-> decltype(j.template get<T>(), void())
+{
+    for (std::size_t i = 0; i < N; ++i)
+    {
+        arr[i] = j.at(i).template get<T>();
+    }
+}
 
-    @pre The passed list @a ranges must have 2, 4, or 6 elements; that is,
-         1, 2, or 3 pairs. This precondition is enforced by an assertion.
+template<typename BasicJsonType, typename ConstructibleArrayType,
+         enable_if_t<
+             std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
+             int> = 0>
+auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, priority_tag<1> /*unused*/)
+-> decltype(
+    arr.reserve(std::declval<typename ConstructibleArrayType::size_type>()),
+    j.template get<typename ConstructibleArrayType::value_type>(),
+    void())
+{
+    using std::end;
 
-    @return true if and only if no range violation was detected
-    */
-    bool next_byte_in_range(std::initializer_list<int> ranges)
+    ConstructibleArrayType ret;
+    ret.reserve(j.size());
+    std::transform(j.begin(), j.end(),
+                   std::inserter(ret, end(ret)), [](const BasicJsonType & i)
     {
-        assert(ranges.size() == 2 or ranges.size() == 4 or ranges.size() == 6);
-        add(current);
+        // get<BasicJsonType>() returns *this, this won't call a from_json
+        // method when value_type is BasicJsonType
+        return i.template get<typename ConstructibleArrayType::value_type>();
+    });
+    arr = std::move(ret);
+}
 
-        for (auto range = ranges.begin(); range != ranges.end(); ++range)
-        {
-            get();
-            if (JSON_LIKELY(*range <= current and current <= *(++range)))
-            {
-                add(current);
-            }
-            else
-            {
-                error_message = "invalid string: ill-formed UTF-8 byte";
-                return false;
-            }
-        }
+template<typename BasicJsonType, typename ConstructibleArrayType,
+         enable_if_t<
+             std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
+             int> = 0>
+void from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr,
+                          priority_tag<0> /*unused*/)
+{
+    using std::end;
 
-        return true;
-    }
+    ConstructibleArrayType ret;
+    std::transform(
+        j.begin(), j.end(), std::inserter(ret, end(ret)),
+        [](const BasicJsonType & i)
+    {
+        // get<BasicJsonType>() returns *this, this won't call a from_json
+        // method when value_type is BasicJsonType
+        return i.template get<typename ConstructibleArrayType::value_type>();
+    });
+    arr = std::move(ret);
+}
 
-    /*!
-    @brief scan a string literal
+template < typename BasicJsonType, typename ConstructibleArrayType,
+           enable_if_t <
+               is_constructible_array_type<BasicJsonType, ConstructibleArrayType>::value&&
+               !is_constructible_object_type<BasicJsonType, ConstructibleArrayType>::value&&
+               !is_constructible_string_type<BasicJsonType, ConstructibleArrayType>::value&&
+               !std::is_same<ConstructibleArrayType, typename BasicJsonType::binary_t>::value&&
+               !is_basic_json<ConstructibleArrayType>::value,
+               int > = 0 >
+auto from_json(const BasicJsonType& j, ConstructibleArrayType& arr)
+-> decltype(from_json_array_impl(j, arr, priority_tag<3> {}),
+j.template get<typename ConstructibleArrayType::value_type>(),
+void())
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
+    }
 
-    This function scans a string according to Sect. 7 of RFC 7159. While
-    scanning, bytes are escaped and copied into buffer token_buffer. Then the
-    function returns successfully, token_buffer is *not* null-terminated (as it
-    may contain \0 bytes), and token_buffer.size() is the number of bytes in the
-    string.
+    from_json_array_impl(j, arr, priority_tag<3> {});
+}
 
-    @return token_type::value_string if string could be successfully scanned,
-            token_type::parse_error otherwise
+template < typename BasicJsonType, typename T, std::size_t... Idx >
+std::array<T, sizeof...(Idx)> from_json_inplace_array_impl(BasicJsonType&& j,
+        identity_tag<std::array<T, sizeof...(Idx)>> /*unused*/, index_sequence<Idx...> /*unused*/)
+{
+    return { { std::forward<BasicJsonType>(j).at(Idx).template get<T>()... } };
+}
 
-    @note In case of errors, variable error_message contains a textual
-          description.
-    */
-    token_type scan_string()
+template < typename BasicJsonType, typename T, std::size_t N >
+auto from_json(BasicJsonType&& j, identity_tag<std::array<T, N>> tag)
+-> decltype(from_json_inplace_array_impl(std::forward<BasicJsonType>(j), tag, make_index_sequence<N> {}))
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
     {
-        // reset token_buffer (ignore opening quote)
-        reset();
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
+    }
 
-        // we entered the function by reading an open quote
-        assert(current == '\"');
+    return from_json_inplace_array_impl(std::forward<BasicJsonType>(j), tag, make_index_sequence<N> {});
+}
 
-        while (true)
-        {
-            // get next character
-            switch (get())
-            {
-                // end of file while parsing string
-                case std::char_traits<char>::eof():
-                {
-                    error_message = "invalid string: missing closing quote";
-                    return token_type::parse_error;
-                }
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, typename BasicJsonType::binary_t& bin)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_binary()))
+    {
+        JSON_THROW(type_error::create(302, "type must be binary, but is " + std::string(j.type_name()), j));
+    }
 
-                // closing quote
-                case '\"':
-                {
-                    return token_type::value_string;
-                }
+    bin = *j.template get_ptr<const typename BasicJsonType::binary_t*>();
+}
 
-                // escapes
-                case '\\':
-                {
-                    switch (get())
-                    {
-                        // quotation mark
-                        case '\"':
-                            add('\"');
-                            break;
-                        // reverse solidus
-                        case '\\':
-                            add('\\');
-                            break;
-                        // solidus
-                        case '/':
-                            add('/');
-                            break;
-                        // backspace
-                        case 'b':
-                            add('\b');
-                            break;
-                        // form feed
-                        case 'f':
-                            add('\f');
-                            break;
-                        // line feed
-                        case 'n':
-                            add('\n');
-                            break;
-                        // carriage return
-                        case 'r':
-                            add('\r');
-                            break;
-                        // tab
-                        case 't':
-                            add('\t');
-                            break;
+template<typename BasicJsonType, typename ConstructibleObjectType,
+         enable_if_t<is_constructible_object_type<BasicJsonType, ConstructibleObjectType>::value, int> = 0>
+void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_object()))
+    {
+        JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name()), j));
+    }
 
-                        // unicode escapes
-                        case 'u':
-                        {
-                            const int codepoint1 = get_codepoint();
-                            int codepoint = codepoint1; // start with codepoint1
+    ConstructibleObjectType ret;
+    const auto* inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
+    using value_type = typename ConstructibleObjectType::value_type;
+    std::transform(
+        inner_object->begin(), inner_object->end(),
+        std::inserter(ret, ret.begin()),
+        [](typename BasicJsonType::object_t::value_type const & p)
+    {
+        return value_type(p.first, p.second.template get<typename ConstructibleObjectType::mapped_type>());
+    });
+    obj = std::move(ret);
+}
 
-                            if (JSON_UNLIKELY(codepoint1 == -1))
-                            {
-                                error_message = "invalid string: '\\u' must be followed by 4 hex digits";
-                                return token_type::parse_error;
-                            }
+// overload for arithmetic types, not chosen for basic_json template arguments
+// (BooleanType, etc..); note: Is it really necessary to provide explicit
+// overloads for boolean_t etc. in case of a custom BooleanType which is not
+// an arithmetic type?
+template < typename BasicJsonType, typename ArithmeticType,
+           enable_if_t <
+               std::is_arithmetic<ArithmeticType>::value&&
+               !std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value&&
+               !std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value&&
+               !std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value&&
+               !std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
+               int > = 0 >
+void from_json(const BasicJsonType& j, ArithmeticType& val)
+{
+    switch (static_cast<value_t>(j))
+    {
+        case value_t::number_unsigned:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
+            break;
+        }
+        case value_t::number_integer:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
+            break;
+        }
+        case value_t::number_float:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
+            break;
+        }
+        case value_t::boolean:
+        {
+            val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>());
+            break;
+        }
 
-                            // check if code point is a high surrogate
-                            if (0xD800 <= codepoint1 and codepoint1 <= 0xDBFF)
-                            {
-                                // expect next \uxxxx entry
-                                if (JSON_LIKELY(get() == '\\' and get() == 'u'))
-                                {
-                                    const int codepoint2 = get_codepoint();
+        case value_t::null:
+        case value_t::object:
+        case value_t::array:
+        case value_t::string:
+        case value_t::binary:
+        case value_t::discarded:
+        default:
+            JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name()), j));
+    }
+}
 
-                                    if (JSON_UNLIKELY(codepoint2 == -1))
-                                    {
-                                        error_message = "invalid string: '\\u' must be followed by 4 hex digits";
-                                        return token_type::parse_error;
-                                    }
+template<typename BasicJsonType, typename... Args, std::size_t... Idx>
+std::tuple<Args...> from_json_tuple_impl_base(BasicJsonType&& j, index_sequence<Idx...> /*unused*/)
+{
+    return std::make_tuple(std::forward<BasicJsonType>(j).at(Idx).template get<Args>()...);
+}
 
-                                    // check if codepoint2 is a low surrogate
-                                    if (JSON_LIKELY(0xDC00 <= codepoint2 and codepoint2 <= 0xDFFF))
-                                    {
-                                        // overwrite codepoint
-                                        codepoint =
-                                            // high surrogate occupies the most significant 22 bits
-                                            (codepoint1 << 10)
-                                            // low surrogate occupies the least significant 15 bits
-                                            + codepoint2
-                                            // there is still the 0xD800, 0xDC00 and 0x10000 noise
-                                            // in the result so we have to subtract with:
-                                            // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
-                                            - 0x35FDC00;
-                                    }
-                                    else
-                                    {
-                                        error_message = "invalid string: surrogate U+DC00..U+DFFF must be followed by U+DC00..U+DFFF";
-                                        return token_type::parse_error;
-                                    }
-                                }
-                                else
-                                {
-                                    error_message = "invalid string: surrogate U+DC00..U+DFFF must be followed by U+DC00..U+DFFF";
-                                    return token_type::parse_error;
-                                }
-                            }
-                            else
-                            {
-                                if (JSON_UNLIKELY(0xDC00 <= codepoint1 and codepoint1 <= 0xDFFF))
-                                {
-                                    error_message = "invalid string: surrogate U+DC00..U+DFFF must follow U+D800..U+DBFF";
-                                    return token_type::parse_error;
-                                }
-                            }
+template < typename BasicJsonType, class A1, class A2 >
+std::pair<A1, A2> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::pair<A1, A2>> /*unused*/, priority_tag<0> /*unused*/)
+{
+    return {std::forward<BasicJsonType>(j).at(0).template get<A1>(),
+            std::forward<BasicJsonType>(j).at(1).template get<A2>()};
+}
 
-                            // result of the above calculation yields a proper codepoint
-                            assert(0x00 <= codepoint and codepoint <= 0x10FFFF);
+template<typename BasicJsonType, typename A1, typename A2>
+void from_json_tuple_impl(BasicJsonType&& j, std::pair<A1, A2>& p, priority_tag<1> /*unused*/)
+{
+    p = from_json_tuple_impl(std::forward<BasicJsonType>(j), identity_tag<std::pair<A1, A2>> {}, priority_tag<0> {});
+}
 
-                            // translate codepoint into bytes
-                            if (codepoint < 0x80)
-                            {
-                                // 1-byte characters: 0xxxxxxx (ASCII)
-                                add(codepoint);
-                            }
-                            else if (codepoint <= 0x7FF)
-                            {
-                                // 2-byte characters: 110xxxxx 10xxxxxx
-                                add(0xC0 | (codepoint >> 6));
-                                add(0x80 | (codepoint & 0x3F));
-                            }
-                            else if (codepoint <= 0xFFFF)
-                            {
-                                // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
-                                add(0xE0 | (codepoint >> 12));
-                                add(0x80 | ((codepoint >> 6) & 0x3F));
-                                add(0x80 | (codepoint & 0x3F));
-                            }
-                            else
-                            {
-                                // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
-                                add(0xF0 | (codepoint >> 18));
-                                add(0x80 | ((codepoint >> 12) & 0x3F));
-                                add(0x80 | ((codepoint >> 6) & 0x3F));
-                                add(0x80 | (codepoint & 0x3F));
-                            }
+template<typename BasicJsonType, typename... Args>
+std::tuple<Args...> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::tuple<Args...>> /*unused*/, priority_tag<2> /*unused*/)
+{
+    return from_json_tuple_impl_base<BasicJsonType, Args...>(std::forward<BasicJsonType>(j), index_sequence_for<Args...> {});
+}
 
-                            break;
-                        }
+template<typename BasicJsonType, typename... Args>
+void from_json_tuple_impl(BasicJsonType&& j, std::tuple<Args...>& t, priority_tag<3> /*unused*/)
+{
+    t = from_json_tuple_impl_base<BasicJsonType, Args...>(std::forward<BasicJsonType>(j), index_sequence_for<Args...> {});
+}
 
-                        // other characters after escape
-                        default:
-                            error_message = "invalid string: forbidden character after backslash";
-                            return token_type::parse_error;
-                    }
+template<typename BasicJsonType, typename TupleRelated>
+auto from_json(BasicJsonType&& j, TupleRelated&& t)
+-> decltype(from_json_tuple_impl(std::forward<BasicJsonType>(j), std::forward<TupleRelated>(t), priority_tag<3> {}))
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
+    }
 
-                    break;
-                }
+    return from_json_tuple_impl(std::forward<BasicJsonType>(j), std::forward<TupleRelated>(t), priority_tag<3> {});
+}
 
-                // invalid control characters
-                case 0x00:
-                {
-                    error_message = "invalid string: control character U+0000 (NUL) must be escaped to \\u0000";
-                    return token_type::parse_error;
-                }
+template < typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
+           typename = enable_if_t < !std::is_constructible <
+                                        typename BasicJsonType::string_t, Key >::value >>
+void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>& m)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
+    }
+    m.clear();
+    for (const auto& p : j)
+    {
+        if (JSON_HEDLEY_UNLIKELY(!p.is_array()))
+        {
+            JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name()), j));
+        }
+        m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
+    }
+}
 
-                case 0x01:
-                {
-                    error_message = "invalid string: control character U+0001 (SOH) must be escaped to \\u0001";
-                    return token_type::parse_error;
-                }
+template < typename BasicJsonType, typename Key, typename Value, typename Hash, typename KeyEqual, typename Allocator,
+           typename = enable_if_t < !std::is_constructible <
+                                        typename BasicJsonType::string_t, Key >::value >>
+void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyEqual, Allocator>& m)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
+    }
+    m.clear();
+    for (const auto& p : j)
+    {
+        if (JSON_HEDLEY_UNLIKELY(!p.is_array()))
+        {
+            JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name()), j));
+        }
+        m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
+    }
+}
 
-                case 0x02:
-                {
-                    error_message = "invalid string: control character U+0002 (STX) must be escaped to \\u0002";
-                    return token_type::parse_error;
-                }
+#ifdef JSON_HAS_CPP_17
+template<typename BasicJsonType>
+void from_json(const BasicJsonType& j, std::filesystem::path& p)
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_string()))
+    {
+        JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name()), j));
+    }
+    p = *j.template get_ptr<const typename BasicJsonType::string_t*>();
+}
+#endif
 
-                case 0x03:
-                {
-                    error_message = "invalid string: control character U+0003 (ETX) must be escaped to \\u0003";
-                    return token_type::parse_error;
-                }
+struct from_json_fn
+{
+    template<typename BasicJsonType, typename T>
+    auto operator()(const BasicJsonType& j, T&& val) const
+    noexcept(noexcept(from_json(j, std::forward<T>(val))))
+    -> decltype(from_json(j, std::forward<T>(val)))
+    {
+        return from_json(j, std::forward<T>(val));
+    }
+};
+}  // namespace detail
 
-                case 0x04:
-                {
-                    error_message = "invalid string: control character U+0004 (EOT) must be escaped to \\u0004";
-                    return token_type::parse_error;
-                }
+/// namespace to hold default `from_json` function
+/// to see why this is required:
+/// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
+namespace // NOLINT(cert-dcl59-cpp,fuchsia-header-anon-namespaces,google-build-namespaces)
+{
+constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value; // NOLINT(misc-definitions-in-headers)
+} // namespace
+} // namespace nlohmann
 
-                case 0x05:
-                {
-                    error_message = "invalid string: control character U+0005 (ENQ) must be escaped to \\u0005";
-                    return token_type::parse_error;
-                }
+// #include <nlohmann/detail/conversions/to_json.hpp>
 
-                case 0x06:
-                {
-                    error_message = "invalid string: control character U+0006 (ACK) must be escaped to \\u0006";
-                    return token_type::parse_error;
-                }
 
-                case 0x07:
-                {
-                    error_message = "invalid string: control character U+0007 (BEL) must be escaped to \\u0007";
-                    return token_type::parse_error;
-                }
+#include <algorithm> // copy
+#include <iterator> // begin, end
+#include <string> // string
+#include <tuple> // tuple, get
+#include <type_traits> // is_same, is_constructible, is_floating_point, is_enum, underlying_type
+#include <utility> // move, forward, declval, pair
+#include <valarray> // valarray
+#include <vector> // vector
 
-                case 0x08:
-                {
-                    error_message = "invalid string: control character U+0008 (BS) must be escaped to \\u0008 or \\b";
-                    return token_type::parse_error;
-                }
+// #include <nlohmann/detail/macro_scope.hpp>
 
-                case 0x09:
-                {
-                    error_message = "invalid string: control character U+0009 (HT) must be escaped to \\u0009 or \\t";
-                    return token_type::parse_error;
-                }
+// #include <nlohmann/detail/iterators/iteration_proxy.hpp>
 
-                case 0x0A:
-                {
-                    error_message = "invalid string: control character U+000A (LF) must be escaped to \\u000A or \\n";
-                    return token_type::parse_error;
-                }
 
-                case 0x0B:
-                {
-                    error_message = "invalid string: control character U+000B (VT) must be escaped to \\u000B";
-                    return token_type::parse_error;
-                }
+#include <cstddef> // size_t
+#include <iterator> // input_iterator_tag
+#include <string> // string, to_string
+#include <tuple> // tuple_size, get, tuple_element
+#include <utility> // move
 
-                case 0x0C:
-                {
-                    error_message = "invalid string: control character U+000C (FF) must be escaped to \\u000C or \\f";
-                    return token_type::parse_error;
-                }
+// #include <nlohmann/detail/meta/type_traits.hpp>
 
-                case 0x0D:
-                {
-                    error_message = "invalid string: control character U+000D (CR) must be escaped to \\u000D or \\r";
-                    return token_type::parse_error;
-                }
+// #include <nlohmann/detail/value_t.hpp>
 
-                case 0x0E:
-                {
-                    error_message = "invalid string: control character U+000E (SO) must be escaped to \\u000E";
-                    return token_type::parse_error;
-                }
 
-                case 0x0F:
-                {
-                    error_message = "invalid string: control character U+000F (SI) must be escaped to \\u000F";
-                    return token_type::parse_error;
-                }
+namespace nlohmann
+{
+namespace detail
+{
+template<typename string_type>
+void int_to_string( string_type& target, std::size_t value )
+{
+    // For ADL
+    using std::to_string;
+    target = to_string(value);
+}
+template<typename IteratorType> class iteration_proxy_value
+{
+  public:
+    using difference_type = std::ptrdiff_t;
+    using value_type = iteration_proxy_value;
+    using pointer = value_type * ;
+    using reference = value_type & ;
+    using iterator_category = std::input_iterator_tag;
+    using string_type = typename std::remove_cv< typename std::remove_reference<decltype( std::declval<IteratorType>().key() ) >::type >::type;
 
-                case 0x10:
-                {
-                    error_message = "invalid string: control character U+0010 (DLE) must be escaped to \\u0010";
-                    return token_type::parse_error;
-                }
+  private:
+    /// the iterator
+    IteratorType anchor;
+    /// an index for arrays (used to create key names)
+    std::size_t array_index = 0;
+    /// last stringified array index
+    mutable std::size_t array_index_last = 0;
+    /// a string representation of the array index
+    mutable string_type array_index_str = "0";
+    /// an empty string (to return a reference for primitive values)
+    const string_type empty_str{};
 
-                case 0x11:
-                {
-                    error_message = "invalid string: control character U+0011 (DC1) must be escaped to \\u0011";
-                    return token_type::parse_error;
-                }
+  public:
+    explicit iteration_proxy_value(IteratorType it) noexcept
+        : anchor(std::move(it))
+    {}
 
-                case 0x12:
-                {
-                    error_message = "invalid string: control character U+0012 (DC2) must be escaped to \\u0012";
-                    return token_type::parse_error;
-                }
+    /// dereference operator (needed for range-based for)
+    iteration_proxy_value& operator*()
+    {
+        return *this;
+    }
 
-                case 0x13:
-                {
-                    error_message = "invalid string: control character U+0013 (DC3) must be escaped to \\u0013";
-                    return token_type::parse_error;
-                }
+    /// increment operator (needed for range-based for)
+    iteration_proxy_value& operator++()
+    {
+        ++anchor;
+        ++array_index;
 
-                case 0x14:
-                {
-                    error_message = "invalid string: control character U+0014 (DC4) must be escaped to \\u0014";
-                    return token_type::parse_error;
-                }
+        return *this;
+    }
 
-                case 0x15:
-                {
-                    error_message = "invalid string: control character U+0015 (NAK) must be escaped to \\u0015";
-                    return token_type::parse_error;
-                }
+    /// equality operator (needed for InputIterator)
+    bool operator==(const iteration_proxy_value& o) const
+    {
+        return anchor == o.anchor;
+    }
 
-                case 0x16:
-                {
-                    error_message = "invalid string: control character U+0016 (SYN) must be escaped to \\u0016";
-                    return token_type::parse_error;
-                }
+    /// inequality operator (needed for range-based for)
+    bool operator!=(const iteration_proxy_value& o) const
+    {
+        return anchor != o.anchor;
+    }
 
-                case 0x17:
-                {
-                    error_message = "invalid string: control character U+0017 (ETB) must be escaped to \\u0017";
-                    return token_type::parse_error;
-                }
+    /// return key of the iterator
+    const string_type& key() const
+    {
+        JSON_ASSERT(anchor.m_object != nullptr);
 
-                case 0x18:
+        switch (anchor.m_object->type())
+        {
+            // use integer array index as key
+            case value_t::array:
+            {
+                if (array_index != array_index_last)
                 {
-                    error_message = "invalid string: control character U+0018 (CAN) must be escaped to \\u0018";
-                    return token_type::parse_error;
+                    int_to_string( array_index_str, array_index );
+                    array_index_last = array_index;
                 }
+                return array_index_str;
+            }
 
-                case 0x19:
-                {
-                    error_message = "invalid string: control character U+0019 (EM) must be escaped to \\u0019";
-                    return token_type::parse_error;
-                }
+            // use key from the object
+            case value_t::object:
+                return anchor.key();
 
-                case 0x1A:
-                {
-                    error_message = "invalid string: control character U+001A (SUB) must be escaped to \\u001A";
-                    return token_type::parse_error;
-                }
+            // use an empty key for all primitive types
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+                return empty_str;
+        }
+    }
 
-                case 0x1B:
-                {
-                    error_message = "invalid string: control character U+001B (ESC) must be escaped to \\u001B";
-                    return token_type::parse_error;
-                }
+    /// return value of the iterator
+    typename IteratorType::reference value() const
+    {
+        return anchor.value();
+    }
+};
 
-                case 0x1C:
-                {
-                    error_message = "invalid string: control character U+001C (FS) must be escaped to \\u001C";
-                    return token_type::parse_error;
-                }
+/// proxy class for the items() function
+template<typename IteratorType> class iteration_proxy
+{
+  private:
+    /// the container to iterate
+    typename IteratorType::reference container;
 
-                case 0x1D:
-                {
-                    error_message = "invalid string: control character U+001D (GS) must be escaped to \\u001D";
-                    return token_type::parse_error;
-                }
+  public:
+    /// construct iteration proxy from a container
+    explicit iteration_proxy(typename IteratorType::reference cont) noexcept
+        : container(cont) {}
 
-                case 0x1E:
-                {
-                    error_message = "invalid string: control character U+001E (RS) must be escaped to \\u001E";
-                    return token_type::parse_error;
-                }
+    /// return iterator begin (needed for range-based for)
+    iteration_proxy_value<IteratorType> begin() noexcept
+    {
+        return iteration_proxy_value<IteratorType>(container.begin());
+    }
 
-                case 0x1F:
-                {
-                    error_message = "invalid string: control character U+001F (US) must be escaped to \\u001F";
-                    return token_type::parse_error;
-                }
+    /// return iterator end (needed for range-based for)
+    iteration_proxy_value<IteratorType> end() noexcept
+    {
+        return iteration_proxy_value<IteratorType>(container.end());
+    }
+};
+// Structured Bindings Support
+// For further reference see https://blog.tartanllama.xyz/structured-bindings/
+// And see https://github.com/nlohmann/json/pull/1391
+template<std::size_t N, typename IteratorType, enable_if_t<N == 0, int> = 0>
+auto get(const nlohmann::detail::iteration_proxy_value<IteratorType>& i) -> decltype(i.key())
+{
+    return i.key();
+}
+// Structured Bindings Support
+// For further reference see https://blog.tartanllama.xyz/structured-bindings/
+// And see https://github.com/nlohmann/json/pull/1391
+template<std::size_t N, typename IteratorType, enable_if_t<N == 1, int> = 0>
+auto get(const nlohmann::detail::iteration_proxy_value<IteratorType>& i) -> decltype(i.value())
+{
+    return i.value();
+}
+}  // namespace detail
+}  // namespace nlohmann
 
-                // U+0020..U+007F (except U+0022 (quote) and U+005C (backspace))
-                case 0x20:
-                case 0x21:
-                case 0x23:
-                case 0x24:
-                case 0x25:
-                case 0x26:
-                case 0x27:
-                case 0x28:
-                case 0x29:
-                case 0x2A:
-                case 0x2B:
-                case 0x2C:
-                case 0x2D:
-                case 0x2E:
-                case 0x2F:
-                case 0x30:
-                case 0x31:
-                case 0x32:
-                case 0x33:
-                case 0x34:
-                case 0x35:
-                case 0x36:
-                case 0x37:
-                case 0x38:
-                case 0x39:
-                case 0x3A:
-                case 0x3B:
-                case 0x3C:
-                case 0x3D:
-                case 0x3E:
-                case 0x3F:
-                case 0x40:
-                case 0x41:
-                case 0x42:
-                case 0x43:
-                case 0x44:
-                case 0x45:
-                case 0x46:
-                case 0x47:
-                case 0x48:
-                case 0x49:
-                case 0x4A:
-                case 0x4B:
-                case 0x4C:
-                case 0x4D:
-                case 0x4E:
-                case 0x4F:
-                case 0x50:
-                case 0x51:
-                case 0x52:
-                case 0x53:
-                case 0x54:
-                case 0x55:
-                case 0x56:
-                case 0x57:
-                case 0x58:
-                case 0x59:
-                case 0x5A:
-                case 0x5B:
-                case 0x5D:
-                case 0x5E:
-                case 0x5F:
-                case 0x60:
-                case 0x61:
-                case 0x62:
-                case 0x63:
-                case 0x64:
-                case 0x65:
-                case 0x66:
-                case 0x67:
-                case 0x68:
-                case 0x69:
-                case 0x6A:
-                case 0x6B:
-                case 0x6C:
-                case 0x6D:
-                case 0x6E:
-                case 0x6F:
-                case 0x70:
-                case 0x71:
-                case 0x72:
-                case 0x73:
-                case 0x74:
-                case 0x75:
-                case 0x76:
-                case 0x77:
-                case 0x78:
-                case 0x79:
-                case 0x7A:
-                case 0x7B:
-                case 0x7C:
-                case 0x7D:
-                case 0x7E:
-                case 0x7F:
-                {
-                    add(current);
-                    break;
-                }
+// The Addition to the STD Namespace is required to add
+// Structured Bindings Support to the iteration_proxy_value class
+// For further reference see https://blog.tartanllama.xyz/structured-bindings/
+// And see https://github.com/nlohmann/json/pull/1391
+namespace std
+{
+#if defined(__clang__)
+    // Fix: https://github.com/nlohmann/json/issues/1401
+    #pragma clang diagnostic push
+    #pragma clang diagnostic ignored "-Wmismatched-tags"
+#endif
+template<typename IteratorType>
+class tuple_size<::nlohmann::detail::iteration_proxy_value<IteratorType>>
+            : public std::integral_constant<std::size_t, 2> {};
 
-                // U+0080..U+07FF: bytes C2..DF 80..BF
-                case 0xC2:
-                case 0xC3:
-                case 0xC4:
-                case 0xC5:
-                case 0xC6:
-                case 0xC7:
-                case 0xC8:
-                case 0xC9:
-                case 0xCA:
-                case 0xCB:
-                case 0xCC:
-                case 0xCD:
-                case 0xCE:
-                case 0xCF:
-                case 0xD0:
-                case 0xD1:
-                case 0xD2:
-                case 0xD3:
-                case 0xD4:
-                case 0xD5:
-                case 0xD6:
-                case 0xD7:
-                case 0xD8:
-                case 0xD9:
-                case 0xDA:
-                case 0xDB:
-                case 0xDC:
-                case 0xDD:
-                case 0xDE:
-                case 0xDF:
-                {
-                    if (JSON_UNLIKELY(not next_byte_in_range({0x80, 0xBF})))
-                    {
-                        return token_type::parse_error;
-                    }
-                    break;
-                }
+template<std::size_t N, typename IteratorType>
+class tuple_element<N, ::nlohmann::detail::iteration_proxy_value<IteratorType >>
+{
+  public:
+    using type = decltype(
+                     get<N>(std::declval <
+                            ::nlohmann::detail::iteration_proxy_value<IteratorType >> ()));
+};
+#if defined(__clang__)
+    #pragma clang diagnostic pop
+#endif
+} // namespace std
 
-                // U+0800..U+0FFF: bytes E0 A0..BF 80..BF
-                case 0xE0:
-                {
-                    if (JSON_UNLIKELY(not (next_byte_in_range({0xA0, 0xBF, 0x80, 0xBF}))))
-                    {
-                        return token_type::parse_error;
-                    }
-                    break;
-                }
+// #include <nlohmann/detail/meta/cpp_future.hpp>
 
-                // U+1000..U+CFFF: bytes E1..EC 80..BF 80..BF
-                // U+E000..U+FFFF: bytes EE..EF 80..BF 80..BF
-                case 0xE1:
-                case 0xE2:
-                case 0xE3:
-                case 0xE4:
-                case 0xE5:
-                case 0xE6:
-                case 0xE7:
-                case 0xE8:
-                case 0xE9:
-                case 0xEA:
-                case 0xEB:
-                case 0xEC:
-                case 0xEE:
-                case 0xEF:
-                {
-                    if (JSON_UNLIKELY(not (next_byte_in_range({0x80, 0xBF, 0x80, 0xBF}))))
-                    {
-                        return token_type::parse_error;
-                    }
-                    break;
-                }
+// #include <nlohmann/detail/meta/type_traits.hpp>
 
-                // U+D000..U+D7FF: bytes ED 80..9F 80..BF
-                case 0xED:
-                {
-                    if (JSON_UNLIKELY(not (next_byte_in_range({0x80, 0x9F, 0x80, 0xBF}))))
-                    {
-                        return token_type::parse_error;
-                    }
-                    break;
-                }
+// #include <nlohmann/detail/value_t.hpp>
 
-                // U+10000..U+3FFFF F0 90..BF 80..BF 80..BF
-                case 0xF0:
-                {
-                    if (JSON_UNLIKELY(not (next_byte_in_range({0x90, 0xBF, 0x80, 0xBF, 0x80, 0xBF}))))
-                    {
-                        return token_type::parse_error;
-                    }
-                    break;
-                }
 
-                // U+40000..U+FFFFF F1..F3 80..BF 80..BF 80..BF
-                case 0xF1:
-                case 0xF2:
-                case 0xF3:
-                {
-                    if (JSON_UNLIKELY(not (next_byte_in_range({0x80, 0xBF, 0x80, 0xBF, 0x80, 0xBF}))))
-                    {
-                        return token_type::parse_error;
-                    }
-                    break;
-                }
+#ifdef JSON_HAS_CPP_17
+    #include <filesystem>
+#endif
 
-                // U+100000..U+10FFFF F4 80..8F 80..BF 80..BF
-                case 0xF4:
-                {
-                    if (JSON_UNLIKELY(not (next_byte_in_range({0x80, 0x8F, 0x80, 0xBF, 0x80, 0xBF}))))
-                    {
-                        return token_type::parse_error;
-                    }
-                    break;
-                }
+namespace nlohmann
+{
+namespace detail
+{
+//////////////////
+// constructors //
+//////////////////
 
-                // remaining bytes (80..C1 and F5..FF) are ill-formed
-                default:
-                {
-                    error_message = "invalid string: ill-formed UTF-8 byte";
-                    return token_type::parse_error;
-                }
-            }
-        }
+/*
+ * Note all external_constructor<>::construct functions need to call
+ * j.m_value.destroy(j.m_type) to avoid a memory leak in case j contains an
+ * allocated value (e.g., a string). See bug issue
+ * https://github.com/nlohmann/json/issues/2865 for more information.
+ */
+
+template<value_t> struct external_constructor;
+
+template<>
+struct external_constructor<value_t::boolean>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::boolean;
+        j.m_value = b;
+        j.assert_invariant();
     }
+};
 
-    static void strtof(float& f, const char* str, char** endptr) noexcept
+template<>
+struct external_constructor<value_t::string>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const typename BasicJsonType::string_t& s)
     {
-        f = std::strtof(str, endptr);
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::string;
+        j.m_value = s;
+        j.assert_invariant();
     }
 
-    static void strtof(double& f, const char* str, char** endptr) noexcept
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::string_t&& s)
     {
-        f = std::strtod(str, endptr);
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::string;
+        j.m_value = std::move(s);
+        j.assert_invariant();
     }
 
-    static void strtof(long double& f, const char* str, char** endptr) noexcept
+    template < typename BasicJsonType, typename CompatibleStringType,
+               enable_if_t < !std::is_same<CompatibleStringType, typename BasicJsonType::string_t>::value,
+                             int > = 0 >
+    static void construct(BasicJsonType& j, const CompatibleStringType& str)
     {
-        f = std::strtold(str, endptr);
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::string;
+        j.m_value.string = j.template create<typename BasicJsonType::string_t>(str);
+        j.assert_invariant();
     }
+};
 
-    /*!
-    @brief scan a number literal
+template<>
+struct external_constructor<value_t::binary>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const typename BasicJsonType::binary_t& b)
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::binary;
+        j.m_value = typename BasicJsonType::binary_t(b);
+        j.assert_invariant();
+    }
 
-    This function scans a string according to Sect. 6 of RFC 7159.
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::binary_t&& b)
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::binary;
+        j.m_value = typename BasicJsonType::binary_t(std::move(b));
+        j.assert_invariant();
+    }
+};
 
-    The function is realized with a deterministic finite state machine derived
-    from the grammar described in RFC 7159. Starting in state "init", the
-    input is read and used to determined the next state. Only state "done"
-    accepts the number. State "error" is a trap state to model errors. In the
-    table below, "anything" means any character but the ones listed before.
+template<>
+struct external_constructor<value_t::number_float>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::number_float;
+        j.m_value = val;
+        j.assert_invariant();
+    }
+};
 
-    state    | 0        | 1-9      | e E      | +       | -       | .        | anything
-    ---------|----------|----------|----------|---------|---------|----------|-----------
-    init     | zero     | any1     | [error]  | [error] | minus   | [error]  | [error]
-    minus    | zero     | any1     | [error]  | [error] | [error] | [error]  | [error]
-    zero     | done     | done     | exponent | done    | done    | decimal1 | done
-    any1     | any1     | any1     | exponent | done    | done    | decimal1 | done
-    decimal1 | decimal2 | [error]  | [error]  | [error] | [error] | [error]  | [error]
-    decimal2 | decimal2 | decimal2 | exponent | done    | done    | done     | done
-    exponent | any2     | any2     | [error]  | sign    | sign    | [error]  | [error]
-    sign     | any2     | any2     | [error]  | [error] | [error] | [error]  | [error]
-    any2     | any2     | any2     | done     | done    | done    | done     | done
+template<>
+struct external_constructor<value_t::number_unsigned>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::number_unsigned_t val) noexcept
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::number_unsigned;
+        j.m_value = val;
+        j.assert_invariant();
+    }
+};
 
-    The state machine is realized with one label per state (prefixed with
-    "scan_number_") and `goto` statements between them. The state machine
-    contains cycles, but any cycle can be left when EOF is read. Therefore,
-    the function is guaranteed to terminate.
+template<>
+struct external_constructor<value_t::number_integer>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::number_integer_t val) noexcept
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::number_integer;
+        j.m_value = val;
+        j.assert_invariant();
+    }
+};
 
-    During scanning, the read bytes are stored in token_buffer. This string is
-    then converted to a signed integer, an unsigned integer, or a
-    floating-point number.
+template<>
+struct external_constructor<value_t::array>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const typename BasicJsonType::array_t& arr)
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::array;
+        j.m_value = arr;
+        j.set_parents();
+        j.assert_invariant();
+    }
 
-    @return token_type::value_unsigned, token_type::value_integer, or
-            token_type::value_float if number could be successfully scanned,
-            token_type::parse_error otherwise
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::array;
+        j.m_value = std::move(arr);
+        j.set_parents();
+        j.assert_invariant();
+    }
 
-    @note The scanner is independent of the current locale. Internally, the
-          locale's decimal point is used instead of `.` to work with the
-          locale-dependent converters.
-    */
-    token_type scan_number()  // lgtm [cpp/use-of-goto]
+    template < typename BasicJsonType, typename CompatibleArrayType,
+               enable_if_t < !std::is_same<CompatibleArrayType, typename BasicJsonType::array_t>::value,
+                             int > = 0 >
+    static void construct(BasicJsonType& j, const CompatibleArrayType& arr)
     {
-        // reset token_buffer to store the number's bytes
-        reset();
+        using std::begin;
+        using std::end;
 
-        // the type of the parsed number; initially set to unsigned; will be
-        // changed if minus sign, decimal point or exponent is read
-        token_type number_type = token_type::value_unsigned;
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::array;
+        j.m_value.array = j.template create<typename BasicJsonType::array_t>(begin(arr), end(arr));
+        j.set_parents();
+        j.assert_invariant();
+    }
 
-        // state (init): we just found out we need to scan a number
-        switch (current)
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const std::vector<bool>& arr)
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::array;
+        j.m_value = value_t::array;
+        j.m_value.array->reserve(arr.size());
+        for (const bool x : arr)
         {
-            case '-':
-            {
-                add(current);
-                goto scan_number_minus;
-            }
-
-            case '0':
-            {
-                add(current);
-                goto scan_number_zero;
-            }
-
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-            {
-                add(current);
-                goto scan_number_any1;
-            }
-
-            // LCOV_EXCL_START
-            default:
-            {
-                // all other characters are rejected outside scan_number()
-                assert(false);
-            }
-                // LCOV_EXCL_STOP
+            j.m_value.array->push_back(x);
+            j.set_parent(j.m_value.array->back());
         }
+        j.assert_invariant();
+    }
 
-scan_number_minus:
-        // state: we just parsed a leading minus sign
-        number_type = token_type::value_integer;
-        switch (get())
+    template<typename BasicJsonType, typename T,
+             enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
+    static void construct(BasicJsonType& j, const std::valarray<T>& arr)
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::array;
+        j.m_value = value_t::array;
+        j.m_value.array->resize(arr.size());
+        if (arr.size() > 0)
         {
-            case '0':
-            {
-                add(current);
-                goto scan_number_zero;
-            }
+            std::copy(std::begin(arr), std::end(arr), j.m_value.array->begin());
+        }
+        j.set_parents();
+        j.assert_invariant();
+    }
+};
 
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-            {
-                add(current);
-                goto scan_number_any1;
-            }
-
-            default:
-            {
-                error_message = "invalid number; expected digit after '-'";
-                return token_type::parse_error;
-            }
-        }
+template<>
+struct external_constructor<value_t::object>
+{
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, const typename BasicJsonType::object_t& obj)
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::object;
+        j.m_value = obj;
+        j.set_parents();
+        j.assert_invariant();
+    }
 
-scan_number_zero:
-        // state: we just parse a zero (maybe with a leading minus sign)
-        switch (get())
-        {
-            case '.':
-            {
-                add(decimal_point_char);
-                goto scan_number_decimal1;
-            }
+    template<typename BasicJsonType>
+    static void construct(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
+    {
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::object;
+        j.m_value = std::move(obj);
+        j.set_parents();
+        j.assert_invariant();
+    }
 
-            case 'e':
-            case 'E':
-            {
-                add(current);
-                goto scan_number_exponent;
-            }
+    template < typename BasicJsonType, typename CompatibleObjectType,
+               enable_if_t < !std::is_same<CompatibleObjectType, typename BasicJsonType::object_t>::value, int > = 0 >
+    static void construct(BasicJsonType& j, const CompatibleObjectType& obj)
+    {
+        using std::begin;
+        using std::end;
 
-            default:
-                goto scan_number_done;
-        }
+        j.m_value.destroy(j.m_type);
+        j.m_type = value_t::object;
+        j.m_value.object = j.template create<typename BasicJsonType::object_t>(begin(obj), end(obj));
+        j.set_parents();
+        j.assert_invariant();
+    }
+};
 
-scan_number_any1:
-        // state: we just parsed a number 0-9 (maybe with a leading minus sign)
-        switch (get())
-        {
-            case '0':
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-            {
-                add(current);
-                goto scan_number_any1;
-            }
+/////////////
+// to_json //
+/////////////
 
-            case '.':
-            {
-                add(decimal_point_char);
-                goto scan_number_decimal1;
-            }
+template<typename BasicJsonType, typename T,
+         enable_if_t<std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
+void to_json(BasicJsonType& j, T b) noexcept
+{
+    external_constructor<value_t::boolean>::construct(j, b);
+}
 
-            case 'e':
-            case 'E':
-            {
-                add(current);
-                goto scan_number_exponent;
-            }
+template<typename BasicJsonType, typename CompatibleString,
+         enable_if_t<std::is_constructible<typename BasicJsonType::string_t, CompatibleString>::value, int> = 0>
+void to_json(BasicJsonType& j, const CompatibleString& s)
+{
+    external_constructor<value_t::string>::construct(j, s);
+}
 
-            default:
-                goto scan_number_done;
-        }
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, typename BasicJsonType::string_t&& s)
+{
+    external_constructor<value_t::string>::construct(j, std::move(s));
+}
 
-scan_number_decimal1:
-        // state: we just parsed a decimal point
-        number_type = token_type::value_float;
-        switch (get())
-        {
-            case '0':
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-            {
-                add(current);
-                goto scan_number_decimal2;
-            }
+template<typename BasicJsonType, typename FloatType,
+         enable_if_t<std::is_floating_point<FloatType>::value, int> = 0>
+void to_json(BasicJsonType& j, FloatType val) noexcept
+{
+    external_constructor<value_t::number_float>::construct(j, static_cast<typename BasicJsonType::number_float_t>(val));
+}
 
-            default:
-            {
-                error_message = "invalid number; expected digit after '.'";
-                return token_type::parse_error;
-            }
-        }
+template<typename BasicJsonType, typename CompatibleNumberUnsignedType,
+         enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t, CompatibleNumberUnsignedType>::value, int> = 0>
+void to_json(BasicJsonType& j, CompatibleNumberUnsignedType val) noexcept
+{
+    external_constructor<value_t::number_unsigned>::construct(j, static_cast<typename BasicJsonType::number_unsigned_t>(val));
+}
 
-scan_number_decimal2:
-        // we just parsed at least one number after a decimal point
-        switch (get())
-        {
-            case '0':
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-            {
-                add(current);
-                goto scan_number_decimal2;
-            }
+template<typename BasicJsonType, typename CompatibleNumberIntegerType,
+         enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t, CompatibleNumberIntegerType>::value, int> = 0>
+void to_json(BasicJsonType& j, CompatibleNumberIntegerType val) noexcept
+{
+    external_constructor<value_t::number_integer>::construct(j, static_cast<typename BasicJsonType::number_integer_t>(val));
+}
 
-            case 'e':
-            case 'E':
-            {
-                add(current);
-                goto scan_number_exponent;
-            }
+template<typename BasicJsonType, typename EnumType,
+         enable_if_t<std::is_enum<EnumType>::value, int> = 0>
+void to_json(BasicJsonType& j, EnumType e) noexcept
+{
+    using underlying_type = typename std::underlying_type<EnumType>::type;
+    external_constructor<value_t::number_integer>::construct(j, static_cast<underlying_type>(e));
+}
 
-            default:
-                goto scan_number_done;
-        }
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, const std::vector<bool>& e)
+{
+    external_constructor<value_t::array>::construct(j, e);
+}
 
-scan_number_exponent:
-        // we just parsed an exponent
-        number_type = token_type::value_float;
-        switch (get())
-        {
-            case '+':
-            case '-':
-            {
-                add(current);
-                goto scan_number_sign;
-            }
+template < typename BasicJsonType, typename CompatibleArrayType,
+           enable_if_t < is_compatible_array_type<BasicJsonType,
+                         CompatibleArrayType>::value&&
+                         !is_compatible_object_type<BasicJsonType, CompatibleArrayType>::value&&
+                         !is_compatible_string_type<BasicJsonType, CompatibleArrayType>::value&&
+                         !std::is_same<typename BasicJsonType::binary_t, CompatibleArrayType>::value&&
+                         !is_basic_json<CompatibleArrayType>::value,
+                         int > = 0 >
+void to_json(BasicJsonType& j, const CompatibleArrayType& arr)
+{
+    external_constructor<value_t::array>::construct(j, arr);
+}
 
-            case '0':
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-            {
-                add(current);
-                goto scan_number_any2;
-            }
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, const typename BasicJsonType::binary_t& bin)
+{
+    external_constructor<value_t::binary>::construct(j, bin);
+}
 
-            default:
-            {
-                error_message =
-                    "invalid number; expected '+', '-', or digit after exponent";
-                return token_type::parse_error;
-            }
-        }
+template<typename BasicJsonType, typename T,
+         enable_if_t<std::is_convertible<T, BasicJsonType>::value, int> = 0>
+void to_json(BasicJsonType& j, const std::valarray<T>& arr)
+{
+    external_constructor<value_t::array>::construct(j, std::move(arr));
+}
 
-scan_number_sign:
-        // we just parsed an exponent sign
-        switch (get())
-        {
-            case '0':
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-            {
-                add(current);
-                goto scan_number_any2;
-            }
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, typename BasicJsonType::array_t&& arr)
+{
+    external_constructor<value_t::array>::construct(j, std::move(arr));
+}
 
-            default:
-            {
-                error_message = "invalid number; expected digit after exponent sign";
-                return token_type::parse_error;
-            }
-        }
+template < typename BasicJsonType, typename CompatibleObjectType,
+           enable_if_t < is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value&& !is_basic_json<CompatibleObjectType>::value, int > = 0 >
+void to_json(BasicJsonType& j, const CompatibleObjectType& obj)
+{
+    external_constructor<value_t::object>::construct(j, obj);
+}
 
-scan_number_any2:
-        // we just parsed a number after the exponent or exponent sign
-        switch (get())
-        {
-            case '0':
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-            {
-                add(current);
-                goto scan_number_any2;
-            }
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
+{
+    external_constructor<value_t::object>::construct(j, std::move(obj));
+}
 
-            default:
-                goto scan_number_done;
-        }
+template <
+    typename BasicJsonType, typename T, std::size_t N,
+    enable_if_t < !std::is_constructible<typename BasicJsonType::string_t,
+                  const T(&)[N]>::value, // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+                  int > = 0 >
+void to_json(BasicJsonType& j, const T(&arr)[N]) // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+{
+    external_constructor<value_t::array>::construct(j, arr);
+}
 
-scan_number_done:
-        // unget the character after the number (we only read it to know that
-        // we are done scanning a number)
-        unget();
+template < typename BasicJsonType, typename T1, typename T2, enable_if_t < std::is_constructible<BasicJsonType, T1>::value&& std::is_constructible<BasicJsonType, T2>::value, int > = 0 >
+void to_json(BasicJsonType& j, const std::pair<T1, T2>& p)
+{
+    j = { p.first, p.second };
+}
 
-        char* endptr = nullptr;
-        errno = 0;
+// for https://github.com/nlohmann/json/pull/1134
+template<typename BasicJsonType, typename T,
+         enable_if_t<std::is_same<T, iteration_proxy_value<typename BasicJsonType::iterator>>::value, int> = 0>
+void to_json(BasicJsonType& j, const T& b)
+{
+    j = { {b.key(), b.value()} };
+}
 
-        // try to parse integers first and fall back to floats
-        if (number_type == token_type::value_unsigned)
-        {
-            const auto x = std::strtoull(token_buffer.data(), &endptr, 10);
+template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
+void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<Idx...> /*unused*/)
+{
+    j = { std::get<Idx>(t)... };
+}
 
-            // we checked the number format before
-            assert(endptr == token_buffer.data() + token_buffer.size());
+template<typename BasicJsonType, typename T, enable_if_t<is_constructible_tuple<BasicJsonType, T>::value, int > = 0>
+void to_json(BasicJsonType& j, const T& t)
+{
+    to_json_tuple_impl(j, t, make_index_sequence<std::tuple_size<T>::value> {});
+}
 
-            if (errno == 0)
-            {
-                value_unsigned = static_cast<number_unsigned_t>(x);
-                if (value_unsigned == x)
-                {
-                    return token_type::value_unsigned;
-                }
-            }
-        }
-        else if (number_type == token_type::value_integer)
-        {
-            const auto x = std::strtoll(token_buffer.data(), &endptr, 10);
+#ifdef JSON_HAS_CPP_17
+template<typename BasicJsonType>
+void to_json(BasicJsonType& j, const std::filesystem::path& p)
+{
+    j = p.string();
+}
+#endif
 
-            // we checked the number format before
-            assert(endptr == token_buffer.data() + token_buffer.size());
+struct to_json_fn
+{
+    template<typename BasicJsonType, typename T>
+    auto operator()(BasicJsonType& j, T&& val) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
+    -> decltype(to_json(j, std::forward<T>(val)), void())
+    {
+        return to_json(j, std::forward<T>(val));
+    }
+};
+}  // namespace detail
 
-            if (errno == 0)
-            {
-                value_integer = static_cast<number_integer_t>(x);
-                if (value_integer == x)
-                {
-                    return token_type::value_integer;
-                }
-            }
-        }
+/// namespace to hold default `to_json` function
+/// to see why this is required:
+/// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
+namespace // NOLINT(cert-dcl59-cpp,fuchsia-header-anon-namespaces,google-build-namespaces)
+{
+constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value; // NOLINT(misc-definitions-in-headers)
+} // namespace
+} // namespace nlohmann
 
-        // this code is reached if we parse a floating-point number or if an
-        // integer conversion above failed
-        strtof(value_float, token_buffer.data(), &endptr);
+// #include <nlohmann/detail/meta/identity_tag.hpp>
 
-        // we checked the number format before
-        assert(endptr == token_buffer.data() + token_buffer.size());
+// #include <nlohmann/detail/meta/type_traits.hpp>
 
-        return token_type::value_float;
-    }
 
+namespace nlohmann
+{
+
+template<typename ValueType, typename>
+struct adl_serializer
+{
     /*!
-    @param[in] literal_text  the literal text to expect
-    @param[in] length        the length of the passed literal text
-    @param[in] return_type   the token type to return on success
+    @brief convert a JSON value to any value type
+
+    This function is usually called by the `get()` function of the
+    @ref basic_json class (either explicit or via conversion operators).
+
+    @note This function is chosen for default-constructible value types.
+
+    @param[in] j        JSON value to read from
+    @param[in,out] val  value to write to
     */
-    token_type scan_literal(const char* literal_text, const std::size_t length,
-                            token_type return_type)
+    template<typename BasicJsonType, typename TargetType = ValueType>
+    static auto from_json(BasicJsonType && j, TargetType& val) noexcept(
+        noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), val)))
+    -> decltype(::nlohmann::from_json(std::forward<BasicJsonType>(j), val), void())
     {
-        assert(current == literal_text[0]);
-        for (std::size_t i = 1; i < length; ++i)
-        {
-            if (JSON_UNLIKELY(get() != literal_text[i]))
-            {
-                error_message = "invalid literal";
-                return token_type::parse_error;
-            }
-        }
-        return return_type;
+        ::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
     }
 
-    /////////////////////
-    // input management
-    /////////////////////
+    /*!
+    @brief convert a JSON value to any value type
 
-    /// reset token_buffer; current character is beginning of token
-    void reset() noexcept
+    This function is usually called by the `get()` function of the
+    @ref basic_json class (either explicit or via conversion operators).
+
+    @note This function is chosen for value types which are not default-constructible.
+
+    @param[in] j  JSON value to read from
+
+    @return copy of the JSON value, converted to @a ValueType
+    */
+    template<typename BasicJsonType, typename TargetType = ValueType>
+    static auto from_json(BasicJsonType && j) noexcept(
+    noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), detail::identity_tag<TargetType> {})))
+    -> decltype(::nlohmann::from_json(std::forward<BasicJsonType>(j), detail::identity_tag<TargetType> {}))
     {
-        token_buffer.clear();
-        token_string.clear();
-        token_string.push_back(std::char_traits<char>::to_char_type(current));
+        return ::nlohmann::from_json(std::forward<BasicJsonType>(j), detail::identity_tag<TargetType> {});
     }
 
-    /*
-    @brief get next character from the input
+    /*!
+    @brief convert any value type to a JSON value
 
-    This function provides the interface to the used input adapter. It does
-    not throw in case the input reached EOF, but returns a
-    `std::char_traits<char>::eof()` in that case.  Stores the scanned characters
-    for use in error messages.
+    This function is usually called by the constructors of the @ref basic_json
+    class.
 
-    @return character read from the input
+    @param[in,out] j  JSON value to write to
+    @param[in] val    value to read from
     */
-    std::char_traits<char>::int_type get()
+    template<typename BasicJsonType, typename TargetType = ValueType>
+    static auto to_json(BasicJsonType& j, TargetType && val) noexcept(
+        noexcept(::nlohmann::to_json(j, std::forward<TargetType>(val))))
+    -> decltype(::nlohmann::to_json(j, std::forward<TargetType>(val)), void())
     {
-        ++position.chars_read_total;
-        ++position.chars_read_current_line;
+        ::nlohmann::to_json(j, std::forward<TargetType>(val));
+    }
+};
+}  // namespace nlohmann
 
-        if (next_unget)
-        {
-            // just reset the next_unget variable and work with current
-            next_unget = false;
-        }
-        else
-        {
-            current = ia->get_character();
-        }
+// #include <nlohmann/byte_container_with_subtype.hpp>
 
-        if (JSON_LIKELY(current != std::char_traits<char>::eof()))
-        {
-            token_string.push_back(std::char_traits<char>::to_char_type(current));
-        }
 
-        if (current == '\n')
-        {
-            ++position.lines_read;
-            ++position.chars_read_current_line = 0;
-        }
+#include <cstdint> // uint8_t, uint64_t
+#include <tuple> // tie
+#include <utility> // move
 
-        return current;
-    }
+namespace nlohmann
+{
 
-    /*!
-    @brief unget current character (read it again on next get)
+/*!
+@brief an internal type for a backed binary type
 
-    We implement unget by setting variable next_unget to true. The input is not
-    changed - we just simulate ungetting by modifying chars_read_total,
-    chars_read_current_line, and token_string. The next call to get() will
-    behave as if the unget character is read again.
-    */
-    void unget()
-    {
-        next_unget = true;
+This type extends the template parameter @a BinaryType provided to `basic_json`
+with a subtype used by BSON and MessagePack. This type exists so that the user
+does not have to specify a type themselves with a specific naming scheme in
+order to override the binary type.
 
-        --position.chars_read_total;
+@tparam BinaryType container to store bytes (`std::vector<std::uint8_t>` by
+                   default)
 
-        // in case we "unget" a newline, we have to also decrement the lines_read
-        if (position.chars_read_current_line == 0)
-        {
-            if (position.lines_read > 0)
-            {
-                --position.lines_read;
-            }
-        }
-        else
-        {
-            --position.chars_read_current_line;
-        }
+@since version 3.8.0; changed type of subtypes to std::uint64_t in 3.10.0.
+*/
+template<typename BinaryType>
+class byte_container_with_subtype : public BinaryType
+{
+  public:
+    /// the type of the underlying container
+    using container_type = BinaryType;
+    /// the type of the subtype
+    using subtype_type = std::uint64_t;
 
-        if (JSON_LIKELY(current != std::char_traits<char>::eof()))
-        {
-            assert(token_string.size() != 0);
-            token_string.pop_back();
-        }
-    }
+    byte_container_with_subtype() noexcept(noexcept(container_type()))
+        : container_type()
+    {}
 
-    /// add a character to token_buffer
-    void add(int c)
-    {
-        token_buffer.push_back(std::char_traits<char>::to_char_type(c));
-    }
+    byte_container_with_subtype(const container_type& b) noexcept(noexcept(container_type(b)))
+        : container_type(b)
+    {}
 
-  public:
-    /////////////////////
-    // value getters
-    /////////////////////
+    byte_container_with_subtype(container_type&& b) noexcept(noexcept(container_type(std::move(b))))
+        : container_type(std::move(b))
+    {}
 
-    /// return integer value
-    constexpr number_integer_t get_number_integer() const noexcept
-    {
-        return value_integer;
-    }
+    byte_container_with_subtype(const container_type& b, subtype_type subtype_) noexcept(noexcept(container_type(b)))
+        : container_type(b)
+        , m_subtype(subtype_)
+        , m_has_subtype(true)
+    {}
 
-    /// return unsigned integer value
-    constexpr number_unsigned_t get_number_unsigned() const noexcept
-    {
-        return value_unsigned;
-    }
+    byte_container_with_subtype(container_type&& b, subtype_type subtype_) noexcept(noexcept(container_type(std::move(b))))
+        : container_type(std::move(b))
+        , m_subtype(subtype_)
+        , m_has_subtype(true)
+    {}
 
-    /// return floating-point value
-    constexpr number_float_t get_number_float() const noexcept
+    bool operator==(const byte_container_with_subtype& rhs) const
     {
-        return value_float;
+        return std::tie(static_cast<const BinaryType&>(*this), m_subtype, m_has_subtype) ==
+               std::tie(static_cast<const BinaryType&>(rhs), rhs.m_subtype, rhs.m_has_subtype);
     }
 
-    /// return current string value (implicitly resets the token; useful only once)
-    string_t& get_string()
+    bool operator!=(const byte_container_with_subtype& rhs) const
     {
-        return token_buffer;
+        return !(rhs == *this);
     }
 
-    /////////////////////
-    // diagnostics
-    /////////////////////
+    /*!
+    @brief sets the binary subtype
 
-    /// return position of last read token
-    constexpr position_t get_position() const noexcept
-    {
-        return position;
-    }
+    Sets the binary subtype of the value, also flags a binary JSON value as
+    having a subtype, which has implications for serialization.
 
-    /// return the last read token (for errors only).  Will never contain EOF
-    /// (an arbitrary value that is not a valid char value, often -1), because
-    /// 255 may legitimately occur.  May contain NUL, which should be escaped.
-    std::string get_token_string() const
-    {
-        // escape control characters
-        std::string result;
-        for (const auto c : token_string)
-        {
-            if ('\x00' <= c and c <= '\x1F')
-            {
-                // escape control characters
-                char cs[9];
-                (std::snprintf)(cs, 9, "<U+%.4X>", static_cast<unsigned char>(c));
-                result += cs;
-            }
-            else
-            {
-                // add character as is
-                result.push_back(c);
-            }
-        }
+    @complexity Constant.
 
-        return result;
-    }
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    /// return syntax error message
-    constexpr const char* get_error_message() const noexcept
+    @sa see @ref subtype() -- return the binary subtype
+    @sa see @ref clear_subtype() -- clears the binary subtype
+    @sa see @ref has_subtype() -- returns whether or not the binary value has a
+    subtype
+
+    @since version 3.8.0
+    */
+    void set_subtype(subtype_type subtype_) noexcept
     {
-        return error_message;
+        m_subtype = subtype_;
+        m_has_subtype = true;
     }
 
-    /////////////////////
-    // actual scanner
-    /////////////////////
-
     /*!
-    @brief skip the UTF-8 byte order mark
-    @return true iff there is no BOM or the correct BOM has been skipped
-    */
-    bool skip_bom()
-    {
-        if (get() == 0xEF)
-        {
-            // check if we completely parse the BOM
-            return get() == 0xBB and get() == 0xBF;
-        }
+    @brief return the binary subtype
 
-        // the first character is not the beginning of the BOM; unget it to
-        // process is later
-        unget();
-        return true;
-    }
+    Returns the numerical subtype of the value if it has a subtype. If it does
+    not have a subtype, this function will return subtype_type(-1) as a sentinel
+    value.
 
-    token_type scan()
-    {
-        // initially, skip the BOM
-        if (position.chars_read_total == 0 and not skip_bom())
-        {
-            error_message = "invalid BOM; must be 0xEF 0xBB 0xBF if given";
-            return token_type::parse_error;
-        }
+    @return the numerical subtype of the binary value
 
-        // read next character and ignore whitespace
-        do
-        {
-            get();
-        }
-        while (current == ' ' or current == '\t' or current == '\n' or current == '\r');
+    @complexity Constant.
 
-        switch (current)
-        {
-            // structural characters
-            case '[':
-                return token_type::begin_array;
-            case ']':
-                return token_type::end_array;
-            case '{':
-                return token_type::begin_object;
-            case '}':
-                return token_type::end_object;
-            case ':':
-                return token_type::name_separator;
-            case ',':
-                return token_type::value_separator;
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-            // literals
-            case 't':
-                return scan_literal("true", 4, token_type::literal_true);
-            case 'f':
-                return scan_literal("false", 5, token_type::literal_false);
-            case 'n':
-                return scan_literal("null", 4, token_type::literal_null);
+    @sa see @ref set_subtype() -- sets the binary subtype
+    @sa see @ref clear_subtype() -- clears the binary subtype
+    @sa see @ref has_subtype() -- returns whether or not the binary value has a
+    subtype
 
-            // string
-            case '\"':
-                return scan_string();
+    @since version 3.8.0; fixed return value to properly return
+           subtype_type(-1) as documented in version 3.10.0
+    */
+    constexpr subtype_type subtype() const noexcept
+    {
+        return m_has_subtype ? m_subtype : subtype_type(-1);
+    }
 
-            // number
-            case '-':
-            case '0':
-            case '1':
-            case '2':
-            case '3':
-            case '4':
-            case '5':
-            case '6':
-            case '7':
-            case '8':
-            case '9':
-                return scan_number();
+    /*!
+    @brief return whether the value has a subtype
 
-            // end of input (the null byte is needed when parsing from
-            // string literals)
-            case '\0':
-            case std::char_traits<char>::eof():
-                return token_type::end_of_input;
+    @return whether the value has a subtype
 
-            // error
-            default:
-                error_message = "invalid literal";
-                return token_type::parse_error;
-        }
-    }
+    @complexity Constant.
 
-  private:
-    /// input adapter
-    detail::input_adapter_t ia = nullptr;
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    /// the current character
-    std::char_traits<char>::int_type current = std::char_traits<char>::eof();
+    @sa see @ref subtype() -- return the binary subtype
+    @sa see @ref set_subtype() -- sets the binary subtype
+    @sa see @ref clear_subtype() -- clears the binary subtype
 
-    /// whether the next get() call should just return current
-    bool next_unget = false;
+    @since version 3.8.0
+    */
+    constexpr bool has_subtype() const noexcept
+    {
+        return m_has_subtype;
+    }
 
-    /// the start position of the current token
-    position_t position;
+    /*!
+    @brief clears the binary subtype
 
-    /// raw input token string (for error messages)
-    std::vector<char> token_string {};
+    Clears the binary subtype and flags the value as not having a subtype, which
+    has implications for serialization; for instance MessagePack will prefer the
+    bin family over the ext family.
 
-    /// buffer for variable-length tokens (numbers, strings)
-    string_t token_buffer {};
+    @complexity Constant.
 
-    /// a description of occurred lexer errors
-    const char* error_message = "";
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
 
-    // number values
-    number_integer_t value_integer = 0;
-    number_unsigned_t value_unsigned = 0;
-    number_float_t value_float = 0;
+    @sa see @ref subtype() -- return the binary subtype
+    @sa see @ref set_subtype() -- sets the binary subtype
+    @sa see @ref has_subtype() -- returns whether or not the binary value has a
+    subtype
 
-    /// the decimal point
-    const char decimal_point_char = '.';
+    @since version 3.8.0
+    */
+    void clear_subtype() noexcept
+    {
+        m_subtype = 0;
+        m_has_subtype = false;
+    }
+
+  private:
+    subtype_type m_subtype = 0;
+    bool m_has_subtype = false;
 };
-}  // namespace detail
-}  // namespace nlohmann
 
-// #include <nlohmann/detail/input/parser.hpp>
+}  // namespace nlohmann
 
+// #include <nlohmann/detail/conversions/from_json.hpp>
 
-#include <cassert> // assert
-#include <cmath> // isfinite
-#include <cstdint> // uint8_t
-#include <functional> // function
-#include <string> // string
-#include <utility> // move
+// #include <nlohmann/detail/conversions/to_json.hpp>
 
 // #include <nlohmann/detail/exceptions.hpp>
 
-// #include <nlohmann/detail/macro_scope.hpp>
-
-// #include <nlohmann/detail/meta/is_sax.hpp>
+// #include <nlohmann/detail/hash.hpp>
 
 
-#include <cstdint> // size_t
-#include <utility> // declval
+#include <cstdint> // uint8_t
+#include <cstddef> // size_t
+#include <functional> // hash
 
-// #include <nlohmann/detail/meta/detected.hpp>
+// #include <nlohmann/detail/macro_scope.hpp>
 
-// #include <nlohmann/detail/meta/type_traits.hpp>
+// #include <nlohmann/detail/value_t.hpp>
 
 
 namespace nlohmann
 {
 namespace detail
 {
-template <typename T>
-using null_function_t = decltype(std::declval<T&>().null());
 
-template <typename T>
-using boolean_function_t =
-    decltype(std::declval<T&>().boolean(std::declval<bool>()));
+// boost::hash_combine
+inline std::size_t combine(std::size_t seed, std::size_t h) noexcept
+{
+    seed ^= h + 0x9e3779b9 + (seed << 6U) + (seed >> 2U);
+    return seed;
+}
 
-template <typename T, typename Integer>
-using number_integer_function_t =
-    decltype(std::declval<T&>().number_integer(std::declval<Integer>()));
+/*!
+@brief hash a JSON value
 
-template <typename T, typename Unsigned>
-using number_unsigned_function_t =
-    decltype(std::declval<T&>().number_unsigned(std::declval<Unsigned>()));
+The hash function tries to rely on std::hash where possible. Furthermore, the
+type of the JSON value is taken into account to have different hash values for
+null, 0, 0U, and false, etc.
 
-template <typename T, typename Float, typename String>
-using number_float_function_t = decltype(std::declval<T&>().number_float(
-                                    std::declval<Float>(), std::declval<const String&>()));
+@tparam BasicJsonType basic_json specialization
+@param j JSON value to hash
+@return hash value of j
+*/
+template<typename BasicJsonType>
+std::size_t hash(const BasicJsonType& j)
+{
+    using string_t = typename BasicJsonType::string_t;
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
 
-template <typename T, typename String>
-using string_function_t =
-    decltype(std::declval<T&>().string(std::declval<String&>()));
+    const auto type = static_cast<std::size_t>(j.type());
+    switch (j.type())
+    {
+        case BasicJsonType::value_t::null:
+        case BasicJsonType::value_t::discarded:
+        {
+            return combine(type, 0);
+        }
 
-template <typename T>
-using start_object_function_t =
-    decltype(std::declval<T&>().start_object(std::declval<std::size_t>()));
+        case BasicJsonType::value_t::object:
+        {
+            auto seed = combine(type, j.size());
+            for (const auto& element : j.items())
+            {
+                const auto h = std::hash<string_t> {}(element.key());
+                seed = combine(seed, h);
+                seed = combine(seed, hash(element.value()));
+            }
+            return seed;
+        }
 
-template <typename T, typename String>
-using key_function_t =
-    decltype(std::declval<T&>().key(std::declval<String&>()));
+        case BasicJsonType::value_t::array:
+        {
+            auto seed = combine(type, j.size());
+            for (const auto& element : j)
+            {
+                seed = combine(seed, hash(element));
+            }
+            return seed;
+        }
 
-template <typename T>
-using end_object_function_t = decltype(std::declval<T&>().end_object());
+        case BasicJsonType::value_t::string:
+        {
+            const auto h = std::hash<string_t> {}(j.template get_ref<const string_t&>());
+            return combine(type, h);
+        }
 
-template <typename T>
-using start_array_function_t =
-    decltype(std::declval<T&>().start_array(std::declval<std::size_t>()));
+        case BasicJsonType::value_t::boolean:
+        {
+            const auto h = std::hash<bool> {}(j.template get<bool>());
+            return combine(type, h);
+        }
 
-template <typename T>
-using end_array_function_t = decltype(std::declval<T&>().end_array());
+        case BasicJsonType::value_t::number_integer:
+        {
+            const auto h = std::hash<number_integer_t> {}(j.template get<number_integer_t>());
+            return combine(type, h);
+        }
 
-template <typename T, typename Exception>
-using parse_error_function_t = decltype(std::declval<T&>().parse_error(
-        std::declval<std::size_t>(), std::declval<const std::string&>(),
-        std::declval<const Exception&>()));
+        case BasicJsonType::value_t::number_unsigned:
+        {
+            const auto h = std::hash<number_unsigned_t> {}(j.template get<number_unsigned_t>());
+            return combine(type, h);
+        }
 
-template <typename SAX, typename BasicJsonType>
-struct is_sax
-{
-  private:
-    static_assert(is_basic_json<BasicJsonType>::value,
-                  "BasicJsonType must be of type basic_json<...>");
+        case BasicJsonType::value_t::number_float:
+        {
+            const auto h = std::hash<number_float_t> {}(j.template get<number_float_t>());
+            return combine(type, h);
+        }
 
-    using number_integer_t = typename BasicJsonType::number_integer_t;
-    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-    using number_float_t = typename BasicJsonType::number_float_t;
-    using string_t = typename BasicJsonType::string_t;
-    using exception_t = typename BasicJsonType::exception;
+        case BasicJsonType::value_t::binary:
+        {
+            auto seed = combine(type, j.get_binary().size());
+            const auto h = std::hash<bool> {}(j.get_binary().has_subtype());
+            seed = combine(seed, h);
+            seed = combine(seed, static_cast<std::size_t>(j.get_binary().subtype()));
+            for (const auto byte : j.get_binary())
+            {
+                seed = combine(seed, std::hash<std::uint8_t> {}(byte));
+            }
+            return seed;
+        }
 
-  public:
-    static constexpr bool value =
-        is_detected_exact<bool, null_function_t, SAX>::value &&
-        is_detected_exact<bool, boolean_function_t, SAX>::value &&
-        is_detected_exact<bool, number_integer_function_t, SAX,
-        number_integer_t>::value &&
-        is_detected_exact<bool, number_unsigned_function_t, SAX,
-        number_unsigned_t>::value &&
-        is_detected_exact<bool, number_float_function_t, SAX, number_float_t,
-        string_t>::value &&
-        is_detected_exact<bool, string_function_t, SAX, string_t>::value &&
-        is_detected_exact<bool, start_object_function_t, SAX>::value &&
-        is_detected_exact<bool, key_function_t, SAX, string_t>::value &&
-        is_detected_exact<bool, end_object_function_t, SAX>::value &&
-        is_detected_exact<bool, start_array_function_t, SAX>::value &&
-        is_detected_exact<bool, end_array_function_t, SAX>::value &&
-        is_detected_exact<bool, parse_error_function_t, SAX, exception_t>::value;
-};
-
-template <typename SAX, typename BasicJsonType>
-struct is_sax_static_asserts
-{
-  private:
-    static_assert(is_basic_json<BasicJsonType>::value,
-                  "BasicJsonType must be of type basic_json<...>");
-
-    using number_integer_t = typename BasicJsonType::number_integer_t;
-    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-    using number_float_t = typename BasicJsonType::number_float_t;
-    using string_t = typename BasicJsonType::string_t;
-    using exception_t = typename BasicJsonType::exception;
+        default:                   // LCOV_EXCL_LINE
+            JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+            return 0;              // LCOV_EXCL_LINE
+    }
+}
 
-  public:
-    static_assert(is_detected_exact<bool, null_function_t, SAX>::value,
-                  "Missing/invalid function: bool null()");
-    static_assert(is_detected_exact<bool, boolean_function_t, SAX>::value,
-                  "Missing/invalid function: bool boolean(bool)");
-    static_assert(is_detected_exact<bool, boolean_function_t, SAX>::value,
-                  "Missing/invalid function: bool boolean(bool)");
-    static_assert(
-        is_detected_exact<bool, number_integer_function_t, SAX,
-        number_integer_t>::value,
-        "Missing/invalid function: bool number_integer(number_integer_t)");
-    static_assert(
-        is_detected_exact<bool, number_unsigned_function_t, SAX,
-        number_unsigned_t>::value,
-        "Missing/invalid function: bool number_unsigned(number_unsigned_t)");
-    static_assert(is_detected_exact<bool, number_float_function_t, SAX,
-                  number_float_t, string_t>::value,
-                  "Missing/invalid function: bool number_float(number_float_t, const string_t&)");
-    static_assert(
-        is_detected_exact<bool, string_function_t, SAX, string_t>::value,
-        "Missing/invalid function: bool string(string_t&)");
-    static_assert(is_detected_exact<bool, start_object_function_t, SAX>::value,
-                  "Missing/invalid function: bool start_object(std::size_t)");
-    static_assert(is_detected_exact<bool, key_function_t, SAX, string_t>::value,
-                  "Missing/invalid function: bool key(string_t&)");
-    static_assert(is_detected_exact<bool, end_object_function_t, SAX>::value,
-                  "Missing/invalid function: bool end_object()");
-    static_assert(is_detected_exact<bool, start_array_function_t, SAX>::value,
-                  "Missing/invalid function: bool start_array(std::size_t)");
-    static_assert(is_detected_exact<bool, end_array_function_t, SAX>::value,
-                  "Missing/invalid function: bool end_array()");
-    static_assert(
-        is_detected_exact<bool, parse_error_function_t, SAX, exception_t>::value,
-        "Missing/invalid function: bool parse_error(std::size_t, const "
-        "std::string&, const exception&)");
-};
 }  // namespace detail
 }  // namespace nlohmann
 
+// #include <nlohmann/detail/input/binary_reader.hpp>
+
+
+#include <algorithm> // generate_n
+#include <array> // array
+#include <cmath> // ldexp
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t, uint16_t, uint32_t, uint64_t
+#include <cstdio> // snprintf
+#include <cstring> // memcpy
+#include <iterator> // back_inserter
+#include <limits> // numeric_limits
+#include <string> // char_traits, string
+#include <utility> // make_pair, move
+#include <vector> // vector
+
+// #include <nlohmann/detail/exceptions.hpp>
+
 // #include <nlohmann/detail/input/input_adapters.hpp>
 
-// #include <nlohmann/detail/input/json_sax.hpp>
 
+#include <array> // array
+#include <cstddef> // size_t
+#include <cstring> // strlen
+#include <iterator> // begin, end, iterator_traits, random_access_iterator_tag, distance, next
+#include <memory> // shared_ptr, make_shared, addressof
+#include <numeric> // accumulate
+#include <string> // string, char_traits
+#include <type_traits> // enable_if, is_base_of, is_pointer, is_integral, remove_pointer
+#include <utility> // pair, declval
 
-#include <cstddef>
-#include <string>
-#include <vector>
+#ifndef JSON_NO_IO
+    #include <cstdio>   // FILE *
+    #include <istream>  // istream
+#endif                  // JSON_NO_IO
 
-// #include <nlohmann/detail/input/parser.hpp>
+// #include <nlohmann/detail/iterators/iterator_traits.hpp>
 
-// #include <nlohmann/detail/exceptions.hpp>
+// #include <nlohmann/detail/macro_scope.hpp>
 
 
 namespace nlohmann
 {
+namespace detail
+{
+/// the supported input formats
+enum class input_format_t { json, cbor, msgpack, ubjson, bson };
+
+////////////////////
+// input adapters //
+////////////////////
 
+#ifndef JSON_NO_IO
 /*!
-@brief SAX interface
+Input adapter for stdio file access. This adapter read only 1 byte and do not use any
+ buffer. This adapter is a very low level adapter.
+*/
+class file_input_adapter
+{
+  public:
+    using char_type = char;
 
-This class describes the SAX interface used by @ref nlohmann::json::sax_parse.
-Each function is called in different situations while the input is parsed. The
-boolean return value informs the parser whether to continue processing the
-input.
+    JSON_HEDLEY_NON_NULL(2)
+    explicit file_input_adapter(std::FILE* f) noexcept
+        : m_file(f)
+    {}
+
+    // make class move-only
+    file_input_adapter(const file_input_adapter&) = delete;
+    file_input_adapter(file_input_adapter&&) noexcept = default;
+    file_input_adapter& operator=(const file_input_adapter&) = delete;
+    file_input_adapter& operator=(file_input_adapter&&) = delete;
+    ~file_input_adapter() = default;
+
+    std::char_traits<char>::int_type get_character() noexcept
+    {
+        return std::fgetc(m_file);
+    }
+
+  private:
+    /// the file pointer to read from
+    std::FILE* m_file;
+};
+
+
+/*!
+Input adapter for a (caching) istream. Ignores a UFT Byte Order Mark at
+beginning of input. Does not support changing the underlying std::streambuf
+in mid-input. Maintains underlying std::istream and std::streambuf to support
+subsequent use of standard std::istream operations to process any input
+characters following those used in parsing the JSON input.  Clears the
+std::istream flags; any input errors (e.g., EOF) will be detected by the first
+subsequent call for input from the std::istream.
 */
-template<typename BasicJsonType>
-struct json_sax
+class input_stream_adapter
 {
-    /// type for (signed) integers
-    using number_integer_t = typename BasicJsonType::number_integer_t;
-    /// type for unsigned integers
-    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-    /// type for floating-point numbers
-    using number_float_t = typename BasicJsonType::number_float_t;
-    /// type for strings
-    using string_t = typename BasicJsonType::string_t;
+  public:
+    using char_type = char;
 
-    /*!
-    @brief a null value was read
-    @return whether parsing should proceed
-    */
-    virtual bool null() = 0;
+    ~input_stream_adapter()
+    {
+        // clear stream flags; we use underlying streambuf I/O, do not
+        // maintain ifstream flags, except eof
+        if (is != nullptr)
+        {
+            is->clear(is->rdstate() & std::ios::eofbit);
+        }
+    }
 
-    /*!
-    @brief a boolean value was read
-    @param[in] val  boolean value
-    @return whether parsing should proceed
-    */
-    virtual bool boolean(bool val) = 0;
+    explicit input_stream_adapter(std::istream& i)
+        : is(&i), sb(i.rdbuf())
+    {}
 
-    /*!
-    @brief an integer number was read
-    @param[in] val  integer value
-    @return whether parsing should proceed
-    */
-    virtual bool number_integer(number_integer_t val) = 0;
+    // delete because of pointer members
+    input_stream_adapter(const input_stream_adapter&) = delete;
+    input_stream_adapter& operator=(input_stream_adapter&) = delete;
+    input_stream_adapter& operator=(input_stream_adapter&&) = delete;
 
-    /*!
-    @brief an unsigned integer number was read
-    @param[in] val  unsigned integer value
-    @return whether parsing should proceed
-    */
-    virtual bool number_unsigned(number_unsigned_t val) = 0;
+    input_stream_adapter(input_stream_adapter&& rhs) noexcept
+        : is(rhs.is), sb(rhs.sb)
+    {
+        rhs.is = nullptr;
+        rhs.sb = nullptr;
+    }
 
-    /*!
-    @brief an floating-point number was read
-    @param[in] val  floating-point value
-    @param[in] s    raw token value
-    @return whether parsing should proceed
-    */
-    virtual bool number_float(number_float_t val, const string_t& s) = 0;
+    // std::istream/std::streambuf use std::char_traits<char>::to_int_type, to
+    // ensure that std::char_traits<char>::eof() and the character 0xFF do not
+    // end up as the same value, eg. 0xFFFFFFFF.
+    std::char_traits<char>::int_type get_character()
+    {
+        auto res = sb->sbumpc();
+        // set eof manually, as we don't use the istream interface.
+        if (JSON_HEDLEY_UNLIKELY(res == std::char_traits<char>::eof()))
+        {
+            is->clear(is->rdstate() | std::ios::eofbit);
+        }
+        return res;
+    }
 
-    /*!
-    @brief a string was read
-    @param[in] val  string value
-    @return whether parsing should proceed
-    @note It is safe to move the passed string.
-    */
-    virtual bool string(string_t& val) = 0;
+  private:
+    /// the associated input stream
+    std::istream* is = nullptr;
+    std::streambuf* sb = nullptr;
+};
+#endif  // JSON_NO_IO
 
-    /*!
-    @brief the beginning of an object was read
-    @param[in] elements  number of object elements or -1 if unknown
-    @return whether parsing should proceed
-    @note binary formats may report the number of elements
-    */
-    virtual bool start_object(std::size_t elements) = 0;
+// General-purpose iterator-based adapter. It might not be as fast as
+// theoretically possible for some containers, but it is extremely versatile.
+template<typename IteratorType>
+class iterator_input_adapter
+{
+  public:
+    using char_type = typename std::iterator_traits<IteratorType>::value_type;
 
-    /*!
-    @brief an object key was read
-    @param[in] val  object key
-    @return whether parsing should proceed
-    @note It is safe to move the passed string.
-    */
-    virtual bool key(string_t& val) = 0;
+    iterator_input_adapter(IteratorType first, IteratorType last)
+        : current(std::move(first)), end(std::move(last))
+    {}
 
-    /*!
-    @brief the end of an object was read
-    @return whether parsing should proceed
-    */
-    virtual bool end_object() = 0;
+    typename std::char_traits<char_type>::int_type get_character()
+    {
+        if (JSON_HEDLEY_LIKELY(current != end))
+        {
+            auto result = std::char_traits<char_type>::to_int_type(*current);
+            std::advance(current, 1);
+            return result;
+        }
 
-    /*!
-    @brief the beginning of an array was read
-    @param[in] elements  number of array elements or -1 if unknown
-    @return whether parsing should proceed
-    @note binary formats may report the number of elements
-    */
-    virtual bool start_array(std::size_t elements) = 0;
+        return std::char_traits<char_type>::eof();
+    }
 
-    /*!
-    @brief the end of an array was read
-    @return whether parsing should proceed
-    */
-    virtual bool end_array() = 0;
+  private:
+    IteratorType current;
+    IteratorType end;
 
-    /*!
-    @brief a parse error occurred
-    @param[in] position    the position in the input where the error occurs
-    @param[in] last_token  the last read token
-    @param[in] ex          an exception object describing the error
-    @return whether parsing should proceed (must return false)
-    */
-    virtual bool parse_error(std::size_t position,
-                             const std::string& last_token,
-                             const detail::exception& ex) = 0;
+    template<typename BaseInputAdapter, size_t T>
+    friend struct wide_string_input_helper;
 
-    virtual ~json_sax() = default;
+    bool empty() const
+    {
+        return current == end;
+    }
 };
 
 
-namespace detail
+template<typename BaseInputAdapter, size_t T>
+struct wide_string_input_helper;
+
+template<typename BaseInputAdapter>
+struct wide_string_input_helper<BaseInputAdapter, 4>
 {
-/*!
-@brief SAX implementation to create a JSON value from SAX events
+    // UTF-32
+    static void fill_buffer(BaseInputAdapter& input,
+                            std::array<std::char_traits<char>::int_type, 4>& utf8_bytes,
+                            size_t& utf8_bytes_index,
+                            size_t& utf8_bytes_filled)
+    {
+        utf8_bytes_index = 0;
 
-This class implements the @ref json_sax interface and processes the SAX events
-to create a JSON value which makes it basically a DOM parser. The structure or
-hierarchy of the JSON value is managed by the stack `ref_stack` which contains
-a pointer to the respective array or object for each recursion depth.
-
-After successful parsing, the value that is passed by reference to the
-constructor contains the parsed value.
-
-@tparam BasicJsonType  the JSON type
-*/
-template<typename BasicJsonType>
-class json_sax_dom_parser
-{
-  public:
-    using number_integer_t = typename BasicJsonType::number_integer_t;
-    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-    using number_float_t = typename BasicJsonType::number_float_t;
-    using string_t = typename BasicJsonType::string_t;
-
-    /*!
-    @param[in, out] r  reference to a JSON value that is manipulated while
-                       parsing
-    @param[in] allow_exceptions_  whether parse errors yield exceptions
-    */
-    explicit json_sax_dom_parser(BasicJsonType& r, const bool allow_exceptions_ = true)
-        : root(r), allow_exceptions(allow_exceptions_)
-    {}
+        if (JSON_HEDLEY_UNLIKELY(input.empty()))
+        {
+            utf8_bytes[0] = std::char_traits<char>::eof();
+            utf8_bytes_filled = 1;
+        }
+        else
+        {
+            // get the current character
+            const auto wc = input.get_character();
 
-    bool null()
-    {
-        handle_value(nullptr);
-        return true;
+            // UTF-32 to UTF-8 encoding
+            if (wc < 0x80)
+            {
+                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(wc);
+                utf8_bytes_filled = 1;
+            }
+            else if (wc <= 0x7FF)
+            {
+                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(0xC0u | ((static_cast<unsigned int>(wc) >> 6u) & 0x1Fu));
+                utf8_bytes[1] = static_cast<std::char_traits<char>::int_type>(0x80u | (static_cast<unsigned int>(wc) & 0x3Fu));
+                utf8_bytes_filled = 2;
+            }
+            else if (wc <= 0xFFFF)
+            {
+                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(0xE0u | ((static_cast<unsigned int>(wc) >> 12u) & 0x0Fu));
+                utf8_bytes[1] = static_cast<std::char_traits<char>::int_type>(0x80u | ((static_cast<unsigned int>(wc) >> 6u) & 0x3Fu));
+                utf8_bytes[2] = static_cast<std::char_traits<char>::int_type>(0x80u | (static_cast<unsigned int>(wc) & 0x3Fu));
+                utf8_bytes_filled = 3;
+            }
+            else if (wc <= 0x10FFFF)
+            {
+                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(0xF0u | ((static_cast<unsigned int>(wc) >> 18u) & 0x07u));
+                utf8_bytes[1] = static_cast<std::char_traits<char>::int_type>(0x80u | ((static_cast<unsigned int>(wc) >> 12u) & 0x3Fu));
+                utf8_bytes[2] = static_cast<std::char_traits<char>::int_type>(0x80u | ((static_cast<unsigned int>(wc) >> 6u) & 0x3Fu));
+                utf8_bytes[3] = static_cast<std::char_traits<char>::int_type>(0x80u | (static_cast<unsigned int>(wc) & 0x3Fu));
+                utf8_bytes_filled = 4;
+            }
+            else
+            {
+                // unknown character
+                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(wc);
+                utf8_bytes_filled = 1;
+            }
+        }
     }
+};
 
-    bool boolean(bool val)
+template<typename BaseInputAdapter>
+struct wide_string_input_helper<BaseInputAdapter, 2>
+{
+    // UTF-16
+    static void fill_buffer(BaseInputAdapter& input,
+                            std::array<std::char_traits<char>::int_type, 4>& utf8_bytes,
+                            size_t& utf8_bytes_index,
+                            size_t& utf8_bytes_filled)
     {
-        handle_value(val);
-        return true;
-    }
+        utf8_bytes_index = 0;
 
-    bool number_integer(number_integer_t val)
-    {
-        handle_value(val);
-        return true;
-    }
+        if (JSON_HEDLEY_UNLIKELY(input.empty()))
+        {
+            utf8_bytes[0] = std::char_traits<char>::eof();
+            utf8_bytes_filled = 1;
+        }
+        else
+        {
+            // get the current character
+            const auto wc = input.get_character();
 
-    bool number_unsigned(number_unsigned_t val)
-    {
-        handle_value(val);
-        return true;
+            // UTF-16 to UTF-8 encoding
+            if (wc < 0x80)
+            {
+                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(wc);
+                utf8_bytes_filled = 1;
+            }
+            else if (wc <= 0x7FF)
+            {
+                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(0xC0u | ((static_cast<unsigned int>(wc) >> 6u)));
+                utf8_bytes[1] = static_cast<std::char_traits<char>::int_type>(0x80u | (static_cast<unsigned int>(wc) & 0x3Fu));
+                utf8_bytes_filled = 2;
+            }
+            else if (0xD800 > wc || wc >= 0xE000)
+            {
+                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(0xE0u | ((static_cast<unsigned int>(wc) >> 12u)));
+                utf8_bytes[1] = static_cast<std::char_traits<char>::int_type>(0x80u | ((static_cast<unsigned int>(wc) >> 6u) & 0x3Fu));
+                utf8_bytes[2] = static_cast<std::char_traits<char>::int_type>(0x80u | (static_cast<unsigned int>(wc) & 0x3Fu));
+                utf8_bytes_filled = 3;
+            }
+            else
+            {
+                if (JSON_HEDLEY_UNLIKELY(!input.empty()))
+                {
+                    const auto wc2 = static_cast<unsigned int>(input.get_character());
+                    const auto charcode = 0x10000u + (((static_cast<unsigned int>(wc) & 0x3FFu) << 10u) | (wc2 & 0x3FFu));
+                    utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(0xF0u | (charcode >> 18u));
+                    utf8_bytes[1] = static_cast<std::char_traits<char>::int_type>(0x80u | ((charcode >> 12u) & 0x3Fu));
+                    utf8_bytes[2] = static_cast<std::char_traits<char>::int_type>(0x80u | ((charcode >> 6u) & 0x3Fu));
+                    utf8_bytes[3] = static_cast<std::char_traits<char>::int_type>(0x80u | (charcode & 0x3Fu));
+                    utf8_bytes_filled = 4;
+                }
+                else
+                {
+                    utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(wc);
+                    utf8_bytes_filled = 1;
+                }
+            }
+        }
     }
+};
 
-    bool number_float(number_float_t val, const string_t& /*unused*/)
-    {
-        handle_value(val);
-        return true;
-    }
+// Wraps another input apdater to convert wide character types into individual bytes.
+template<typename BaseInputAdapter, typename WideCharType>
+class wide_string_input_adapter
+{
+  public:
+    using char_type = char;
 
-    bool string(string_t& val)
-    {
-        handle_value(val);
-        return true;
-    }
+    wide_string_input_adapter(BaseInputAdapter base)
+        : base_adapter(base) {}
 
-    bool start_object(std::size_t len)
+    typename std::char_traits<char>::int_type get_character() noexcept
     {
-        ref_stack.push_back(handle_value(BasicJsonType::value_t::object));
-
-        if (JSON_UNLIKELY(len != std::size_t(-1) and len > ref_stack.back()->max_size()))
+        // check if buffer needs to be filled
+        if (utf8_bytes_index == utf8_bytes_filled)
         {
-            JSON_THROW(out_of_range::create(408,
-                                            "excessive object size: " + std::to_string(len)));
+            fill_buffer<sizeof(WideCharType)>();
+
+            JSON_ASSERT(utf8_bytes_filled > 0);
+            JSON_ASSERT(utf8_bytes_index == 0);
         }
 
-        return true;
+        // use buffer
+        JSON_ASSERT(utf8_bytes_filled > 0);
+        JSON_ASSERT(utf8_bytes_index < utf8_bytes_filled);
+        return utf8_bytes[utf8_bytes_index++];
     }
 
-    bool key(string_t& val)
-    {
-        // add null at given key and store the reference for later
-        object_element = &(ref_stack.back()->m_value.object->operator[](val));
-        return true;
-    }
+  private:
+    BaseInputAdapter base_adapter;
 
-    bool end_object()
+    template<size_t T>
+    void fill_buffer()
     {
-        ref_stack.pop_back();
-        return true;
+        wide_string_input_helper<BaseInputAdapter, T>::fill_buffer(base_adapter, utf8_bytes, utf8_bytes_index, utf8_bytes_filled);
     }
 
-    bool start_array(std::size_t len)
-    {
-        ref_stack.push_back(handle_value(BasicJsonType::value_t::array));
-
-        if (JSON_UNLIKELY(len != std::size_t(-1) and len > ref_stack.back()->max_size()))
-        {
-            JSON_THROW(out_of_range::create(408,
-                                            "excessive array size: " + std::to_string(len)));
-        }
+    /// a buffer for UTF-8 bytes
+    std::array<std::char_traits<char>::int_type, 4> utf8_bytes = {{0, 0, 0, 0}};
 
-        return true;
-    }
+    /// index to the utf8_codes array for the next valid byte
+    std::size_t utf8_bytes_index = 0;
+    /// number of valid bytes in the utf8_codes array
+    std::size_t utf8_bytes_filled = 0;
+};
 
-    bool end_array()
-    {
-        ref_stack.pop_back();
-        return true;
-    }
 
-    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/,
-                     const detail::exception& ex)
-    {
-        errored = true;
-        if (allow_exceptions)
-        {
-            // determine the proper exception type from the id
-            switch ((ex.id / 100) % 100)
-            {
-                case 1:
-                    JSON_THROW(*reinterpret_cast<const detail::parse_error*>(&ex));
-                case 4:
-                    JSON_THROW(*reinterpret_cast<const detail::out_of_range*>(&ex));
-                // LCOV_EXCL_START
-                case 2:
-                    JSON_THROW(*reinterpret_cast<const detail::invalid_iterator*>(&ex));
-                case 3:
-                    JSON_THROW(*reinterpret_cast<const detail::type_error*>(&ex));
-                case 5:
-                    JSON_THROW(*reinterpret_cast<const detail::other_error*>(&ex));
-                default:
-                    assert(false);
-                    // LCOV_EXCL_STOP
-            }
-        }
-        return false;
-    }
+template<typename IteratorType, typename Enable = void>
+struct iterator_input_adapter_factory
+{
+    using iterator_type = IteratorType;
+    using char_type = typename std::iterator_traits<iterator_type>::value_type;
+    using adapter_type = iterator_input_adapter<iterator_type>;
 
-    constexpr bool is_errored() const
+    static adapter_type create(IteratorType first, IteratorType last)
     {
-        return errored;
+        return adapter_type(std::move(first), std::move(last));
     }
+};
 
-  private:
-    /*!
-    @invariant If the ref stack is empty, then the passed value will be the new
-               root.
-    @invariant If the ref stack contains a value, then it is an array or an
-               object to which we can add elements
-    */
-    template<typename Value>
-    BasicJsonType* handle_value(Value&& v)
+template<typename T>
+struct is_iterator_of_multibyte
+{
+    using value_type = typename std::iterator_traits<T>::value_type;
+    enum
     {
-        if (ref_stack.empty())
-        {
-            root = BasicJsonType(std::forward<Value>(v));
-            return &root;
-        }
+        value = sizeof(value_type) > 1
+    };
+};
 
-        assert(ref_stack.back()->is_array() or ref_stack.back()->is_object());
+template<typename IteratorType>
+struct iterator_input_adapter_factory<IteratorType, enable_if_t<is_iterator_of_multibyte<IteratorType>::value>>
+{
+    using iterator_type = IteratorType;
+    using char_type = typename std::iterator_traits<iterator_type>::value_type;
+    using base_adapter_type = iterator_input_adapter<iterator_type>;
+    using adapter_type = wide_string_input_adapter<base_adapter_type, char_type>;
 
-        if (ref_stack.back()->is_array())
-        {
-            ref_stack.back()->m_value.array->emplace_back(std::forward<Value>(v));
-            return &(ref_stack.back()->m_value.array->back());
-        }
-        else
-        {
-            assert(object_element);
-            *object_element = BasicJsonType(std::forward<Value>(v));
-            return object_element;
-        }
+    static adapter_type create(IteratorType first, IteratorType last)
+    {
+        return adapter_type(base_adapter_type(std::move(first), std::move(last)));
     }
-
-    /// the parsed JSON value
-    BasicJsonType& root;
-    /// stack to model hierarchy of values
-    std::vector<BasicJsonType*> ref_stack;
-    /// helper to hold the reference for the next object element
-    BasicJsonType* object_element = nullptr;
-    /// whether a syntax error occurred
-    bool errored = false;
-    /// whether to throw exceptions in case of errors
-    const bool allow_exceptions = true;
 };
 
-template<typename BasicJsonType>
-class json_sax_dom_callback_parser
+// General purpose iterator-based input
+template<typename IteratorType>
+typename iterator_input_adapter_factory<IteratorType>::adapter_type input_adapter(IteratorType first, IteratorType last)
 {
-  public:
-    using number_integer_t = typename BasicJsonType::number_integer_t;
-    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-    using number_float_t = typename BasicJsonType::number_float_t;
-    using string_t = typename BasicJsonType::string_t;
-    using parser_callback_t = typename BasicJsonType::parser_callback_t;
-    using parse_event_t = typename BasicJsonType::parse_event_t;
+    using factory_type = iterator_input_adapter_factory<IteratorType>;
+    return factory_type::create(first, last);
+}
 
-    json_sax_dom_callback_parser(BasicJsonType& r,
-                                 const parser_callback_t cb,
-                                 const bool allow_exceptions_ = true)
-        : root(r), callback(cb), allow_exceptions(allow_exceptions_)
-    {
-        keep_stack.push_back(true);
-    }
+// Convenience shorthand from container to iterator
+// Enables ADL on begin(container) and end(container)
+// Encloses the using declarations in namespace for not to leak them to outside scope
 
-    bool null()
-    {
-        handle_value(nullptr);
-        return true;
-    }
+namespace container_input_adapter_factory_impl
+{
 
-    bool boolean(bool val)
-    {
-        handle_value(val);
-        return true;
-    }
+using std::begin;
+using std::end;
 
-    bool number_integer(number_integer_t val)
-    {
-        handle_value(val);
-        return true;
-    }
+template<typename ContainerType, typename Enable = void>
+struct container_input_adapter_factory {};
 
-    bool number_unsigned(number_unsigned_t val)
-    {
-        handle_value(val);
-        return true;
-    }
+template<typename ContainerType>
+struct container_input_adapter_factory< ContainerType,
+       void_t<decltype(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>()))>>
+       {
+           using adapter_type = decltype(input_adapter(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>())));
 
-    bool number_float(number_float_t val, const string_t& /*unused*/)
-    {
-        handle_value(val);
-        return true;
-    }
-
-    bool string(string_t& val)
-    {
-        handle_value(val);
-        return true;
-    }
+           static adapter_type create(const ContainerType& container)
+{
+    return input_adapter(begin(container), end(container));
+}
+       };
 
-    bool start_object(std::size_t len)
-    {
-        // check callback for object start
-        const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::object_start, discarded);
-        keep_stack.push_back(keep);
+} // namespace container_input_adapter_factory_impl
 
-        auto val = handle_value(BasicJsonType::value_t::object, true);
-        ref_stack.push_back(val.second);
+template<typename ContainerType>
+typename container_input_adapter_factory_impl::container_input_adapter_factory<ContainerType>::adapter_type input_adapter(const ContainerType& container)
+{
+    return container_input_adapter_factory_impl::container_input_adapter_factory<ContainerType>::create(container);
+}
 
-        // check object limit
-        if (ref_stack.back())
-        {
-            if (JSON_UNLIKELY(len != std::size_t(-1) and len > ref_stack.back()->max_size()))
-            {
-                JSON_THROW(out_of_range::create(408,
-                                                "excessive object size: " + std::to_string(len)));
-            }
-        }
+#ifndef JSON_NO_IO
+// Special cases with fast paths
+inline file_input_adapter input_adapter(std::FILE* file)
+{
+    return file_input_adapter(file);
+}
 
-        return true;
-    }
+inline input_stream_adapter input_adapter(std::istream& stream)
+{
+    return input_stream_adapter(stream);
+}
 
-    bool key(string_t& val)
-    {
-        BasicJsonType k = BasicJsonType(val);
+inline input_stream_adapter input_adapter(std::istream&& stream)
+{
+    return input_stream_adapter(stream);
+}
+#endif  // JSON_NO_IO
+
+using contiguous_bytes_input_adapter = decltype(input_adapter(std::declval<const char*>(), std::declval<const char*>()));
+
+// Null-delimited strings, and the like.
+template < typename CharT,
+           typename std::enable_if <
+               std::is_pointer<CharT>::value&&
+               !std::is_array<CharT>::value&&
+               std::is_integral<typename std::remove_pointer<CharT>::type>::value&&
+               sizeof(typename std::remove_pointer<CharT>::type) == 1,
+               int >::type = 0 >
+contiguous_bytes_input_adapter input_adapter(CharT b)
+{
+    auto length = std::strlen(reinterpret_cast<const char*>(b));
+    const auto* ptr = reinterpret_cast<const char*>(b);
+    return input_adapter(ptr, ptr + length);
+}
 
-        // check callback for key
-        const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::key, k);
-        key_keep_stack.push_back(keep);
+template<typename T, std::size_t N>
+auto input_adapter(T (&array)[N]) -> decltype(input_adapter(array, array + N)) // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+{
+    return input_adapter(array, array + N);
+}
 
-        // add discarded value at given key and store the reference for later
-        if (keep and ref_stack.back())
-        {
-            object_element = &(ref_stack.back()->m_value.object->operator[](val) = discarded);
-        }
+// This class only handles inputs of input_buffer_adapter type.
+// It's required so that expressions like {ptr, len} can be implicitely casted
+// to the correct adapter.
+class span_input_adapter
+{
+  public:
+    template < typename CharT,
+               typename std::enable_if <
+                   std::is_pointer<CharT>::value&&
+                   std::is_integral<typename std::remove_pointer<CharT>::type>::value&&
+                   sizeof(typename std::remove_pointer<CharT>::type) == 1,
+                   int >::type = 0 >
+    span_input_adapter(CharT b, std::size_t l)
+        : ia(reinterpret_cast<const char*>(b), reinterpret_cast<const char*>(b) + l) {}
 
-        return true;
-    }
+    template<class IteratorType,
+             typename std::enable_if<
+                 std::is_same<typename iterator_traits<IteratorType>::iterator_category, std::random_access_iterator_tag>::value,
+                 int>::type = 0>
+    span_input_adapter(IteratorType first, IteratorType last)
+        : ia(input_adapter(first, last)) {}
 
-    bool end_object()
+    contiguous_bytes_input_adapter&& get()
     {
-        if (ref_stack.back())
-        {
-            if (not callback(static_cast<int>(ref_stack.size()) - 1, parse_event_t::object_end, *ref_stack.back()))
-            {
-                // discard object
-                *ref_stack.back() = discarded;
-            }
-        }
+        return std::move(ia); // NOLINT(hicpp-move-const-arg,performance-move-const-arg)
+    }
 
-        assert(not ref_stack.empty());
-        assert(not keep_stack.empty());
-        ref_stack.pop_back();
-        keep_stack.pop_back();
+  private:
+    contiguous_bytes_input_adapter ia;
+};
+}  // namespace detail
+}  // namespace nlohmann
 
-        if (not ref_stack.empty() and ref_stack.back())
-        {
-            // remove discarded value
-            if (ref_stack.back()->is_object())
-            {
-                for (auto it = ref_stack.back()->begin(); it != ref_stack.back()->end(); ++it)
-                {
-                    if (it->is_discarded())
-                    {
-                        ref_stack.back()->erase(it);
-                        break;
-                    }
-                }
-            }
-        }
+// #include <nlohmann/detail/input/json_sax.hpp>
 
-        return true;
-    }
 
-    bool start_array(std::size_t len)
-    {
-        const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::array_start, discarded);
-        keep_stack.push_back(keep);
+#include <cstddef>
+#include <string> // string
+#include <utility> // move
+#include <vector> // vector
 
-        auto val = handle_value(BasicJsonType::value_t::array, true);
-        ref_stack.push_back(val.second);
+// #include <nlohmann/detail/exceptions.hpp>
 
-        // check array limit
-        if (ref_stack.back())
-        {
-            if (JSON_UNLIKELY(len != std::size_t(-1) and len > ref_stack.back()->max_size()))
-            {
-                JSON_THROW(out_of_range::create(408,
-                                                "excessive array size: " + std::to_string(len)));
-            }
-        }
+// #include <nlohmann/detail/macro_scope.hpp>
 
-        return true;
-    }
 
-    bool end_array()
-    {
-        bool keep = true;
+namespace nlohmann
+{
 
-        if (ref_stack.back())
-        {
-            keep = callback(static_cast<int>(ref_stack.size()) - 1, parse_event_t::array_end, *ref_stack.back());
-            if (not keep)
-            {
-                // discard array
-                *ref_stack.back() = discarded;
-            }
-        }
+/*!
+@brief SAX interface
 
-        assert(not ref_stack.empty());
-        assert(not keep_stack.empty());
-        ref_stack.pop_back();
-        keep_stack.pop_back();
+This class describes the SAX interface used by @ref nlohmann::json::sax_parse.
+Each function is called in different situations while the input is parsed. The
+boolean return value informs the parser whether to continue processing the
+input.
+*/
+template<typename BasicJsonType>
+struct json_sax
+{
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using string_t = typename BasicJsonType::string_t;
+    using binary_t = typename BasicJsonType::binary_t;
 
-        // remove discarded value
-        if (not keep and not ref_stack.empty())
-        {
-            if (ref_stack.back()->is_array())
-            {
-                ref_stack.back()->m_value.array->pop_back();
-            }
-        }
+    /*!
+    @brief a null value was read
+    @return whether parsing should proceed
+    */
+    virtual bool null() = 0;
 
-        return true;
-    }
+    /*!
+    @brief a boolean value was read
+    @param[in] val  boolean value
+    @return whether parsing should proceed
+    */
+    virtual bool boolean(bool val) = 0;
 
-    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/,
-                     const detail::exception& ex)
-    {
-        errored = true;
-        if (allow_exceptions)
-        {
-            // determine the proper exception type from the id
-            switch ((ex.id / 100) % 100)
-            {
-                case 1:
-                    JSON_THROW(*reinterpret_cast<const detail::parse_error*>(&ex));
-                case 4:
-                    JSON_THROW(*reinterpret_cast<const detail::out_of_range*>(&ex));
-                // LCOV_EXCL_START
-                case 2:
-                    JSON_THROW(*reinterpret_cast<const detail::invalid_iterator*>(&ex));
-                case 3:
-                    JSON_THROW(*reinterpret_cast<const detail::type_error*>(&ex));
-                case 5:
-                    JSON_THROW(*reinterpret_cast<const detail::other_error*>(&ex));
-                default:
-                    assert(false);
-                    // LCOV_EXCL_STOP
-            }
-        }
-        return false;
-    }
+    /*!
+    @brief an integer number was read
+    @param[in] val  integer value
+    @return whether parsing should proceed
+    */
+    virtual bool number_integer(number_integer_t val) = 0;
 
-    constexpr bool is_errored() const
-    {
-        return errored;
-    }
+    /*!
+    @brief an unsigned integer number was read
+    @param[in] val  unsigned integer value
+    @return whether parsing should proceed
+    */
+    virtual bool number_unsigned(number_unsigned_t val) = 0;
 
-  private:
     /*!
-    @param[in] v  value to add to the JSON value we build during parsing
-    @param[in] skip_callback  whether we should skip calling the callback
-               function; this is required after start_array() and
-               start_object() SAX events, because otherwise we would call the
-               callback function with an empty array or object, respectively.
+    @brief an floating-point number was read
+    @param[in] val  floating-point value
+    @param[in] s    raw token value
+    @return whether parsing should proceed
+    */
+    virtual bool number_float(number_float_t val, const string_t& s) = 0;
 
-    @invariant If the ref stack is empty, then the passed value will be the new
-               root.
-    @invariant If the ref stack contains a value, then it is an array or an
-               object to which we can add elements
+    /*!
+    @brief a string was read
+    @param[in] val  string value
+    @return whether parsing should proceed
+    @note It is safe to move the passed string.
+    */
+    virtual bool string(string_t& val) = 0;
 
-    @return pair of boolean (whether value should be kept) and pointer (to the
-            passed value in the ref_stack hierarchy; nullptr if not kept)
+    /*!
+    @brief a binary string was read
+    @param[in] val  binary value
+    @return whether parsing should proceed
+    @note It is safe to move the passed binary.
     */
-    template<typename Value>
-    std::pair<bool, BasicJsonType*> handle_value(Value&& v, const bool skip_callback = false)
-    {
-        assert(not keep_stack.empty());
+    virtual bool binary(binary_t& val) = 0;
 
-        // do not handle this value if we know it would be added to a discarded
-        // container
-        if (not keep_stack.back())
-        {
-            return {false, nullptr};
-        }
+    /*!
+    @brief the beginning of an object was read
+    @param[in] elements  number of object elements or -1 if unknown
+    @return whether parsing should proceed
+    @note binary formats may report the number of elements
+    */
+    virtual bool start_object(std::size_t elements) = 0;
 
-        // create value
-        auto value = BasicJsonType(std::forward<Value>(v));
+    /*!
+    @brief an object key was read
+    @param[in] val  object key
+    @return whether parsing should proceed
+    @note It is safe to move the passed string.
+    */
+    virtual bool key(string_t& val) = 0;
 
-        // check callback
-        const bool keep = skip_callback or callback(static_cast<int>(ref_stack.size()), parse_event_t::value, value);
+    /*!
+    @brief the end of an object was read
+    @return whether parsing should proceed
+    */
+    virtual bool end_object() = 0;
 
-        // do not handle this value if we just learnt it shall be discarded
-        if (not keep)
-        {
-            return {false, nullptr};
-        }
+    /*!
+    @brief the beginning of an array was read
+    @param[in] elements  number of array elements or -1 if unknown
+    @return whether parsing should proceed
+    @note binary formats may report the number of elements
+    */
+    virtual bool start_array(std::size_t elements) = 0;
 
-        if (ref_stack.empty())
-        {
-            root = std::move(value);
-            return {true, &root};
-        }
+    /*!
+    @brief the end of an array was read
+    @return whether parsing should proceed
+    */
+    virtual bool end_array() = 0;
 
-        // skip this value if we already decided to skip the parent
-        // (https://github.com/nlohmann/json/issues/971#issuecomment-413678360)
-        if (not ref_stack.back())
-        {
-            return {false, nullptr};
-        }
+    /*!
+    @brief a parse error occurred
+    @param[in] position    the position in the input where the error occurs
+    @param[in] last_token  the last read token
+    @param[in] ex          an exception object describing the error
+    @return whether parsing should proceed (must return false)
+    */
+    virtual bool parse_error(std::size_t position,
+                             const std::string& last_token,
+                             const detail::exception& ex) = 0;
 
-        // we now only expect arrays and objects
-        assert(ref_stack.back()->is_array() or ref_stack.back()->is_object());
+    json_sax() = default;
+    json_sax(const json_sax&) = default;
+    json_sax(json_sax&&) noexcept = default;
+    json_sax& operator=(const json_sax&) = default;
+    json_sax& operator=(json_sax&&) noexcept = default;
+    virtual ~json_sax() = default;
+};
 
-        if (ref_stack.back()->is_array())
-        {
-            ref_stack.back()->m_value.array->push_back(std::move(value));
-            return {true, &(ref_stack.back()->m_value.array->back())};
-        }
-        else
-        {
-            // check if we should store an element for the current key
-            assert(not key_keep_stack.empty());
-            const bool store_element = key_keep_stack.back();
-            key_keep_stack.pop_back();
 
-            if (not store_element)
-            {
-                return {false, nullptr};
-            }
+namespace detail
+{
+/*!
+@brief SAX implementation to create a JSON value from SAX events
 
-            assert(object_element);
-            *object_element = std::move(value);
-            return {true, object_element};
-        }
-    }
+This class implements the @ref json_sax interface and processes the SAX events
+to create a JSON value which makes it basically a DOM parser. The structure or
+hierarchy of the JSON value is managed by the stack `ref_stack` which contains
+a pointer to the respective array or object for each recursion depth.
 
-    /// the parsed JSON value
-    BasicJsonType& root;
-    /// stack to model hierarchy of values
-    std::vector<BasicJsonType*> ref_stack;
-    /// stack to manage which values to keep
-    std::vector<bool> keep_stack;
-    /// stack to manage which object keys to keep
-    std::vector<bool> key_keep_stack;
-    /// helper to hold the reference for the next object element
-    BasicJsonType* object_element = nullptr;
-    /// whether a syntax error occurred
-    bool errored = false;
-    /// callback function
-    const parser_callback_t callback = nullptr;
-    /// whether to throw exceptions in case of errors
-    const bool allow_exceptions = true;
-    /// a discarded value for the callback
-    BasicJsonType discarded = BasicJsonType::value_t::discarded;
-};
+After successful parsing, the value that is passed by reference to the
+constructor contains the parsed value.
 
+@tparam BasicJsonType  the JSON type
+*/
 template<typename BasicJsonType>
-class json_sax_acceptor
+class json_sax_dom_parser
 {
   public:
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
     using string_t = typename BasicJsonType::string_t;
+    using binary_t = typename BasicJsonType::binary_t;
+
+    /*!
+    @param[in,out] r  reference to a JSON value that is manipulated while
+                       parsing
+    @param[in] allow_exceptions_  whether parse errors yield exceptions
+    */
+    explicit json_sax_dom_parser(BasicJsonType& r, const bool allow_exceptions_ = true)
+        : root(r), allow_exceptions(allow_exceptions_)
+    {}
+
+    // make class move-only
+    json_sax_dom_parser(const json_sax_dom_parser&) = delete;
+    json_sax_dom_parser(json_sax_dom_parser&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
+    json_sax_dom_parser& operator=(const json_sax_dom_parser&) = delete;
+    json_sax_dom_parser& operator=(json_sax_dom_parser&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
+    ~json_sax_dom_parser() = default;
 
     bool null()
     {
+        handle_value(nullptr);
         return true;
     }
 
-    bool boolean(bool /*unused*/)
+    bool boolean(bool val)
     {
+        handle_value(val);
         return true;
     }
 
-    bool number_integer(number_integer_t /*unused*/)
+    bool number_integer(number_integer_t val)
     {
+        handle_value(val);
         return true;
     }
 
-    bool number_unsigned(number_unsigned_t /*unused*/)
+    bool number_unsigned(number_unsigned_t val)
     {
+        handle_value(val);
         return true;
     }
 
-    bool number_float(number_float_t /*unused*/, const string_t& /*unused*/)
+    bool number_float(number_float_t val, const string_t& /*unused*/)
+    {
+        handle_value(val);
+        return true;
+    }
+
+    bool string(string_t& val)
     {
+        handle_value(val);
         return true;
     }
 
-    bool string(string_t& /*unused*/)
+    bool binary(binary_t& val)
     {
+        handle_value(std::move(val));
         return true;
     }
 
-    bool start_object(std::size_t  /*unused*/ = std::size_t(-1))
+    bool start_object(std::size_t len)
     {
+        ref_stack.push_back(handle_value(BasicJsonType::value_t::object));
+
+        if (JSON_HEDLEY_UNLIKELY(len != std::size_t(-1) && len > ref_stack.back()->max_size()))
+        {
+            JSON_THROW(out_of_range::create(408, "excessive object size: " + std::to_string(len), *ref_stack.back()));
+        }
+
         return true;
     }
 
-    bool key(string_t& /*unused*/)
+    bool key(string_t& val)
     {
+        // add null at given key and store the reference for later
+        object_element = &(ref_stack.back()->m_value.object->operator[](val));
         return true;
     }
 
     bool end_object()
     {
+        ref_stack.back()->set_parents();
+        ref_stack.pop_back();
         return true;
     }
 
-    bool start_array(std::size_t  /*unused*/ = std::size_t(-1))
+    bool start_array(std::size_t len)
     {
+        ref_stack.push_back(handle_value(BasicJsonType::value_t::array));
+
+        if (JSON_HEDLEY_UNLIKELY(len != std::size_t(-1) && len > ref_stack.back()->max_size()))
+        {
+            JSON_THROW(out_of_range::create(408, "excessive array size: " + std::to_string(len), *ref_stack.back()));
+        }
+
         return true;
     }
 
     bool end_array()
     {
+        ref_stack.back()->set_parents();
+        ref_stack.pop_back();
         return true;
     }
 
-    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/, const detail::exception& /*unused*/)
+    template<class Exception>
+    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/,
+                     const Exception& ex)
     {
+        errored = true;
+        static_cast<void>(ex);
+        if (allow_exceptions)
+        {
+            JSON_THROW(ex);
+        }
         return false;
     }
-};
-}  // namespace detail
 
-}  // namespace nlohmann
+    constexpr bool is_errored() const
+    {
+        return errored;
+    }
 
-// #include <nlohmann/detail/input/lexer.hpp>
+  private:
+    /*!
+    @invariant If the ref stack is empty, then the passed value will be the new
+               root.
+    @invariant If the ref stack contains a value, then it is an array or an
+               object to which we can add elements
+    */
+    template<typename Value>
+    JSON_HEDLEY_RETURNS_NON_NULL
+    BasicJsonType* handle_value(Value&& v)
+    {
+        if (ref_stack.empty())
+        {
+            root = BasicJsonType(std::forward<Value>(v));
+            return &root;
+        }
 
-// #include <nlohmann/detail/value_t.hpp>
+        JSON_ASSERT(ref_stack.back()->is_array() || ref_stack.back()->is_object());
 
+        if (ref_stack.back()->is_array())
+        {
+            ref_stack.back()->m_value.array->emplace_back(std::forward<Value>(v));
+            return &(ref_stack.back()->m_value.array->back());
+        }
 
-namespace nlohmann
-{
-namespace detail
-{
-////////////
-// parser //
-////////////
+        JSON_ASSERT(ref_stack.back()->is_object());
+        JSON_ASSERT(object_element);
+        *object_element = BasicJsonType(std::forward<Value>(v));
+        return object_element;
+    }
 
-/*!
-@brief syntax analysis
+    /// the parsed JSON value
+    BasicJsonType& root;
+    /// stack to model hierarchy of values
+    std::vector<BasicJsonType*> ref_stack {};
+    /// helper to hold the reference for the next object element
+    BasicJsonType* object_element = nullptr;
+    /// whether a syntax error occurred
+    bool errored = false;
+    /// whether to throw exceptions in case of errors
+    const bool allow_exceptions = true;
+};
 
-This class implements a recursive decent parser.
-*/
 template<typename BasicJsonType>
-class parser
+class json_sax_dom_callback_parser
 {
+  public:
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
     using string_t = typename BasicJsonType::string_t;
-    using lexer_t = lexer<BasicJsonType>;
-    using token_type = typename lexer_t::token_type;
+    using binary_t = typename BasicJsonType::binary_t;
+    using parser_callback_t = typename BasicJsonType::parser_callback_t;
+    using parse_event_t = typename BasicJsonType::parse_event_t;
 
-  public:
-    enum class parse_event_t : uint8_t
-    {
-        /// the parser read `{` and started to process a JSON object
-        object_start,
-        /// the parser read `}` and finished processing a JSON object
-        object_end,
-        /// the parser read `[` and started to process a JSON array
-        array_start,
-        /// the parser read `]` and finished processing a JSON array
-        array_end,
-        /// the parser read a key of a value in an object
-        key,
-        /// the parser finished reading a JSON value
-        value
-    };
+    json_sax_dom_callback_parser(BasicJsonType& r,
+                                 const parser_callback_t cb,
+                                 const bool allow_exceptions_ = true)
+        : root(r), callback(cb), allow_exceptions(allow_exceptions_)
+    {
+        keep_stack.push_back(true);
+    }
 
-    using parser_callback_t =
-        std::function<bool(int depth, parse_event_t event, BasicJsonType& parsed)>;
+    // make class move-only
+    json_sax_dom_callback_parser(const json_sax_dom_callback_parser&) = delete;
+    json_sax_dom_callback_parser(json_sax_dom_callback_parser&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
+    json_sax_dom_callback_parser& operator=(const json_sax_dom_callback_parser&) = delete;
+    json_sax_dom_callback_parser& operator=(json_sax_dom_callback_parser&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
+    ~json_sax_dom_callback_parser() = default;
 
-    /// a parser reading from an input adapter
-    explicit parser(detail::input_adapter_t&& adapter,
-                    const parser_callback_t cb = nullptr,
-                    const bool allow_exceptions_ = true)
-        : callback(cb), m_lexer(std::move(adapter)), allow_exceptions(allow_exceptions_)
+    bool null()
     {
-        // read first token
-        get_token();
+        handle_value(nullptr);
+        return true;
     }
 
-    /*!
-    @brief public parser interface
+    bool boolean(bool val)
+    {
+        handle_value(val);
+        return true;
+    }
 
-    @param[in] strict      whether to expect the last token to be EOF
-    @param[in,out] result  parsed JSON value
+    bool number_integer(number_integer_t val)
+    {
+        handle_value(val);
+        return true;
+    }
 
-    @throw parse_error.101 in case of an unexpected token
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
-    */
-    void parse(const bool strict, BasicJsonType& result)
+    bool number_unsigned(number_unsigned_t val)
     {
-        if (callback)
-        {
-            json_sax_dom_callback_parser<BasicJsonType> sdp(result, callback, allow_exceptions);
-            sax_parse_internal(&sdp);
-            result.assert_invariant();
+        handle_value(val);
+        return true;
+    }
 
-            // in strict mode, input must be completely read
-            if (strict and (get_token() != token_type::end_of_input))
-            {
-                sdp.parse_error(m_lexer.get_position(),
-                                m_lexer.get_token_string(),
-                                parse_error::create(101, m_lexer.get_position(),
-                                                    exception_message(token_type::end_of_input, "value")));
-            }
+    bool number_float(number_float_t val, const string_t& /*unused*/)
+    {
+        handle_value(val);
+        return true;
+    }
 
-            // in case of an error, return discarded value
-            if (sdp.is_errored())
-            {
-                result = value_t::discarded;
-                return;
-            }
+    bool string(string_t& val)
+    {
+        handle_value(val);
+        return true;
+    }
 
-            // set top-level value to null if it was discarded by the callback
-            // function
-            if (result.is_discarded())
-            {
-                result = nullptr;
-            }
-        }
-        else
-        {
-            json_sax_dom_parser<BasicJsonType> sdp(result, allow_exceptions);
-            sax_parse_internal(&sdp);
-            result.assert_invariant();
+    bool binary(binary_t& val)
+    {
+        handle_value(std::move(val));
+        return true;
+    }
 
-            // in strict mode, input must be completely read
-            if (strict and (get_token() != token_type::end_of_input))
-            {
-                sdp.parse_error(m_lexer.get_position(),
-                                m_lexer.get_token_string(),
-                                parse_error::create(101, m_lexer.get_position(),
-                                                    exception_message(token_type::end_of_input, "value")));
-            }
+    bool start_object(std::size_t len)
+    {
+        // check callback for object start
+        const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::object_start, discarded);
+        keep_stack.push_back(keep);
 
-            // in case of an error, return discarded value
-            if (sdp.is_errored())
-            {
-                result = value_t::discarded;
-                return;
-            }
-        }
-    }
+        auto val = handle_value(BasicJsonType::value_t::object, true);
+        ref_stack.push_back(val.second);
 
-    /*!
-    @brief public accept interface
+        // check object limit
+        if (ref_stack.back() && JSON_HEDLEY_UNLIKELY(len != std::size_t(-1) && len > ref_stack.back()->max_size()))
+        {
+            JSON_THROW(out_of_range::create(408, "excessive object size: " + std::to_string(len), *ref_stack.back()));
+        }
 
-    @param[in] strict  whether to expect the last token to be EOF
-    @return whether the input is a proper JSON text
-    */
-    bool accept(const bool strict = true)
-    {
-        json_sax_acceptor<BasicJsonType> sax_acceptor;
-        return sax_parse(&sax_acceptor, strict);
+        return true;
     }
 
-    template <typename SAX>
-    bool sax_parse(SAX* sax, const bool strict = true)
+    bool key(string_t& val)
     {
-        (void)detail::is_sax_static_asserts<SAX, BasicJsonType> {};
-        const bool result = sax_parse_internal(sax);
+        BasicJsonType k = BasicJsonType(val);
 
-        // strict mode: next byte must be EOF
-        if (result and strict and (get_token() != token_type::end_of_input))
+        // check callback for key
+        const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::key, k);
+        key_keep_stack.push_back(keep);
+
+        // add discarded value at given key and store the reference for later
+        if (keep && ref_stack.back())
         {
-            return sax->parse_error(m_lexer.get_position(),
-                                    m_lexer.get_token_string(),
-                                    parse_error::create(101, m_lexer.get_position(),
-                                            exception_message(token_type::end_of_input, "value")));
+            object_element = &(ref_stack.back()->m_value.object->operator[](val) = discarded);
         }
 
-        return result;
+        return true;
     }
 
-  private:
-    template <typename SAX>
-    bool sax_parse_internal(SAX* sax)
+    bool end_object()
     {
-        // stack to remember the hierarchy of structured values we are parsing
-        // true = array; false = object
-        std::vector<bool> states;
-        // value to avoid a goto (see comment where set to true)
-        bool skip_to_state_evaluation = false;
+        if (ref_stack.back())
+        {
+            if (!callback(static_cast<int>(ref_stack.size()) - 1, parse_event_t::object_end, *ref_stack.back()))
+            {
+                // discard object
+                *ref_stack.back() = discarded;
+            }
+            else
+            {
+                ref_stack.back()->set_parents();
+            }
+        }
 
-        while (true)
+        JSON_ASSERT(!ref_stack.empty());
+        JSON_ASSERT(!keep_stack.empty());
+        ref_stack.pop_back();
+        keep_stack.pop_back();
+
+        if (!ref_stack.empty() && ref_stack.back() && ref_stack.back()->is_structured())
         {
-            if (not skip_to_state_evaluation)
+            // remove discarded value
+            for (auto it = ref_stack.back()->begin(); it != ref_stack.back()->end(); ++it)
             {
-                // invariant: get_token() was called before each iteration
-                switch (last_token)
+                if (it->is_discarded())
                 {
-                    case token_type::begin_object:
-                    {
-                        if (JSON_UNLIKELY(not sax->start_object(std::size_t(-1))))
-                        {
-                            return false;
-                        }
+                    ref_stack.back()->erase(it);
+                    break;
+                }
+            }
+        }
 
-                        // closing } -> we are done
-                        if (get_token() == token_type::end_object)
-                        {
-                            if (JSON_UNLIKELY(not sax->end_object()))
-                            {
-                                return false;
-                            }
-                            break;
-                        }
+        return true;
+    }
 
-                        // parse key
-                        if (JSON_UNLIKELY(last_token != token_type::value_string))
-                        {
-                            return sax->parse_error(m_lexer.get_position(),
-                                                    m_lexer.get_token_string(),
-                                                    parse_error::create(101, m_lexer.get_position(),
-                                                            exception_message(token_type::value_string, "object key")));
-                        }
-                        if (JSON_UNLIKELY(not sax->key(m_lexer.get_string())))
-                        {
-                            return false;
-                        }
+    bool start_array(std::size_t len)
+    {
+        const bool keep = callback(static_cast<int>(ref_stack.size()), parse_event_t::array_start, discarded);
+        keep_stack.push_back(keep);
 
-                        // parse separator (:)
-                        if (JSON_UNLIKELY(get_token() != token_type::name_separator))
-                        {
-                            return sax->parse_error(m_lexer.get_position(),
-                                                    m_lexer.get_token_string(),
-                                                    parse_error::create(101, m_lexer.get_position(),
-                                                            exception_message(token_type::name_separator, "object separator")));
-                        }
+        auto val = handle_value(BasicJsonType::value_t::array, true);
+        ref_stack.push_back(val.second);
 
-                        // remember we are now inside an object
-                        states.push_back(false);
+        // check array limit
+        if (ref_stack.back() && JSON_HEDLEY_UNLIKELY(len != std::size_t(-1) && len > ref_stack.back()->max_size()))
+        {
+            JSON_THROW(out_of_range::create(408, "excessive array size: " + std::to_string(len), *ref_stack.back()));
+        }
 
-                        // parse values
-                        get_token();
-                        continue;
-                    }
+        return true;
+    }
 
-                    case token_type::begin_array:
-                    {
-                        if (JSON_UNLIKELY(not sax->start_array(std::size_t(-1))))
-                        {
-                            return false;
-                        }
+    bool end_array()
+    {
+        bool keep = true;
 
-                        // closing ] -> we are done
-                        if (get_token() == token_type::end_array)
-                        {
-                            if (JSON_UNLIKELY(not sax->end_array()))
-                            {
-                                return false;
-                            }
-                            break;
-                        }
+        if (ref_stack.back())
+        {
+            keep = callback(static_cast<int>(ref_stack.size()) - 1, parse_event_t::array_end, *ref_stack.back());
+            if (keep)
+            {
+                ref_stack.back()->set_parents();
+            }
+            else
+            {
+                // discard array
+                *ref_stack.back() = discarded;
+            }
+        }
 
-                        // remember we are now inside an array
-                        states.push_back(true);
+        JSON_ASSERT(!ref_stack.empty());
+        JSON_ASSERT(!keep_stack.empty());
+        ref_stack.pop_back();
+        keep_stack.pop_back();
 
-                        // parse values (no need to call get_token)
-                        continue;
-                    }
+        // remove discarded value
+        if (!keep && !ref_stack.empty() && ref_stack.back()->is_array())
+        {
+            ref_stack.back()->m_value.array->pop_back();
+        }
 
-                    case token_type::value_float:
-                    {
-                        const auto res = m_lexer.get_number_float();
+        return true;
+    }
 
-                        if (JSON_UNLIKELY(not std::isfinite(res)))
-                        {
-                            return sax->parse_error(m_lexer.get_position(),
-                                                    m_lexer.get_token_string(),
-                                                    out_of_range::create(406, "number overflow parsing '" + m_lexer.get_token_string() + "'"));
-                        }
-                        else
-                        {
-                            if (JSON_UNLIKELY(not sax->number_float(res, m_lexer.get_string())))
-                            {
-                                return false;
-                            }
-                            break;
-                        }
-                    }
+    template<class Exception>
+    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/,
+                     const Exception& ex)
+    {
+        errored = true;
+        static_cast<void>(ex);
+        if (allow_exceptions)
+        {
+            JSON_THROW(ex);
+        }
+        return false;
+    }
 
-                    case token_type::literal_false:
-                    {
-                        if (JSON_UNLIKELY(not sax->boolean(false)))
-                        {
-                            return false;
-                        }
-                        break;
-                    }
+    constexpr bool is_errored() const
+    {
+        return errored;
+    }
 
-                    case token_type::literal_null:
-                    {
-                        if (JSON_UNLIKELY(not sax->null()))
-                        {
-                            return false;
-                        }
-                        break;
-                    }
+  private:
+    /*!
+    @param[in] v  value to add to the JSON value we build during parsing
+    @param[in] skip_callback  whether we should skip calling the callback
+               function; this is required after start_array() and
+               start_object() SAX events, because otherwise we would call the
+               callback function with an empty array or object, respectively.
 
-                    case token_type::literal_true:
-                    {
-                        if (JSON_UNLIKELY(not sax->boolean(true)))
-                        {
-                            return false;
-                        }
-                        break;
-                    }
+    @invariant If the ref stack is empty, then the passed value will be the new
+               root.
+    @invariant If the ref stack contains a value, then it is an array or an
+               object to which we can add elements
 
-                    case token_type::value_integer:
-                    {
-                        if (JSON_UNLIKELY(not sax->number_integer(m_lexer.get_number_integer())))
-                        {
-                            return false;
-                        }
-                        break;
-                    }
+    @return pair of boolean (whether value should be kept) and pointer (to the
+            passed value in the ref_stack hierarchy; nullptr if not kept)
+    */
+    template<typename Value>
+    std::pair<bool, BasicJsonType*> handle_value(Value&& v, const bool skip_callback = false)
+    {
+        JSON_ASSERT(!keep_stack.empty());
 
-                    case token_type::value_string:
-                    {
-                        if (JSON_UNLIKELY(not sax->string(m_lexer.get_string())))
-                        {
-                            return false;
-                        }
-                        break;
-                    }
+        // do not handle this value if we know it would be added to a discarded
+        // container
+        if (!keep_stack.back())
+        {
+            return {false, nullptr};
+        }
 
-                    case token_type::value_unsigned:
-                    {
-                        if (JSON_UNLIKELY(not sax->number_unsigned(m_lexer.get_number_unsigned())))
-                        {
-                            return false;
-                        }
-                        break;
-                    }
+        // create value
+        auto value = BasicJsonType(std::forward<Value>(v));
 
-                    case token_type::parse_error:
-                    {
-                        // using "uninitialized" to avoid "expected" message
-                        return sax->parse_error(m_lexer.get_position(),
-                                                m_lexer.get_token_string(),
-                                                parse_error::create(101, m_lexer.get_position(),
-                                                        exception_message(token_type::uninitialized, "value")));
-                    }
+        // check callback
+        const bool keep = skip_callback || callback(static_cast<int>(ref_stack.size()), parse_event_t::value, value);
 
-                    default: // the last token was unexpected
-                    {
-                        return sax->parse_error(m_lexer.get_position(),
-                                                m_lexer.get_token_string(),
-                                                parse_error::create(101, m_lexer.get_position(),
-                                                        exception_message(token_type::literal_or_value, "value")));
-                    }
-                }
-            }
-            else
-            {
-                skip_to_state_evaluation = false;
-            }
-
-            // we reached this line after we successfully parsed a value
-            if (states.empty())
-            {
-                // empty stack: we reached the end of the hierarchy: done
-                return true;
-            }
-            else
-            {
-                if (states.back())  // array
-                {
-                    // comma -> next value
-                    if (get_token() == token_type::value_separator)
-                    {
-                        // parse a new value
-                        get_token();
-                        continue;
-                    }
-
-                    // closing ]
-                    if (JSON_LIKELY(last_token == token_type::end_array))
-                    {
-                        if (JSON_UNLIKELY(not sax->end_array()))
-                        {
-                            return false;
-                        }
-
-                        // We are done with this array. Before we can parse a
-                        // new value, we need to evaluate the new state first.
-                        // By setting skip_to_state_evaluation to false, we
-                        // are effectively jumping to the beginning of this if.
-                        assert(not states.empty());
-                        states.pop_back();
-                        skip_to_state_evaluation = true;
-                        continue;
-                    }
-                    else
-                    {
-                        return sax->parse_error(m_lexer.get_position(),
-                                                m_lexer.get_token_string(),
-                                                parse_error::create(101, m_lexer.get_position(),
-                                                        exception_message(token_type::end_array, "array")));
-                    }
-                }
-                else  // object
-                {
-                    // comma -> next value
-                    if (get_token() == token_type::value_separator)
-                    {
-                        // parse key
-                        if (JSON_UNLIKELY(get_token() != token_type::value_string))
-                        {
-                            return sax->parse_error(m_lexer.get_position(),
-                                                    m_lexer.get_token_string(),
-                                                    parse_error::create(101, m_lexer.get_position(),
-                                                            exception_message(token_type::value_string, "object key")));
-                        }
-                        else
-                        {
-                            if (JSON_UNLIKELY(not sax->key(m_lexer.get_string())))
-                            {
-                                return false;
-                            }
-                        }
-
-                        // parse separator (:)
-                        if (JSON_UNLIKELY(get_token() != token_type::name_separator))
-                        {
-                            return sax->parse_error(m_lexer.get_position(),
-                                                    m_lexer.get_token_string(),
-                                                    parse_error::create(101, m_lexer.get_position(),
-                                                            exception_message(token_type::name_separator, "object separator")));
-                        }
-
-                        // parse values
-                        get_token();
-                        continue;
-                    }
-
-                    // closing }
-                    if (JSON_LIKELY(last_token == token_type::end_object))
-                    {
-                        if (JSON_UNLIKELY(not sax->end_object()))
-                        {
-                            return false;
-                        }
-
-                        // We are done with this object. Before we can parse a
-                        // new value, we need to evaluate the new state first.
-                        // By setting skip_to_state_evaluation to false, we
-                        // are effectively jumping to the beginning of this if.
-                        assert(not states.empty());
-                        states.pop_back();
-                        skip_to_state_evaluation = true;
-                        continue;
-                    }
-                    else
-                    {
-                        return sax->parse_error(m_lexer.get_position(),
-                                                m_lexer.get_token_string(),
-                                                parse_error::create(101, m_lexer.get_position(),
-                                                        exception_message(token_type::end_object, "object")));
-                    }
-                }
-            }
+        // do not handle this value if we just learnt it shall be discarded
+        if (!keep)
+        {
+            return {false, nullptr};
         }
-    }
-
-    /// get next token from lexer
-    token_type get_token()
-    {
-        return (last_token = m_lexer.scan());
-    }
-
-    std::string exception_message(const token_type expected, const std::string& context)
-    {
-        std::string error_msg = "syntax error ";
 
-        if (not context.empty())
+        if (ref_stack.empty())
         {
-            error_msg += "while parsing " + context + " ";
+            root = std::move(value);
+            return {true, &root};
         }
 
-        error_msg += "- ";
-
-        if (last_token == token_type::parse_error)
+        // skip this value if we already decided to skip the parent
+        // (https://github.com/nlohmann/json/issues/971#issuecomment-413678360)
+        if (!ref_stack.back())
         {
-            error_msg += std::string(m_lexer.get_error_message()) + "; last read: '" +
-                         m_lexer.get_token_string() + "'";
+            return {false, nullptr};
         }
-        else
+
+        // we now only expect arrays and objects
+        JSON_ASSERT(ref_stack.back()->is_array() || ref_stack.back()->is_object());
+
+        // array
+        if (ref_stack.back()->is_array())
         {
-            error_msg += "unexpected " + std::string(lexer_t::token_type_name(last_token));
+            ref_stack.back()->m_value.array->emplace_back(std::move(value));
+            return {true, &(ref_stack.back()->m_value.array->back())};
         }
 
-        if (expected != token_type::uninitialized)
+        // object
+        JSON_ASSERT(ref_stack.back()->is_object());
+        // check if we should store an element for the current key
+        JSON_ASSERT(!key_keep_stack.empty());
+        const bool store_element = key_keep_stack.back();
+        key_keep_stack.pop_back();
+
+        if (!store_element)
         {
-            error_msg += "; expected " + std::string(lexer_t::token_type_name(expected));
+            return {false, nullptr};
         }
 
-        return error_msg;
+        JSON_ASSERT(object_element);
+        *object_element = std::move(value);
+        return {true, object_element};
     }
 
-  private:
+    /// the parsed JSON value
+    BasicJsonType& root;
+    /// stack to model hierarchy of values
+    std::vector<BasicJsonType*> ref_stack {};
+    /// stack to manage which values to keep
+    std::vector<bool> keep_stack {};
+    /// stack to manage which object keys to keep
+    std::vector<bool> key_keep_stack {};
+    /// helper to hold the reference for the next object element
+    BasicJsonType* object_element = nullptr;
+    /// whether a syntax error occurred
+    bool errored = false;
     /// callback function
     const parser_callback_t callback = nullptr;
-    /// the type of the last read token
-    token_type last_token = token_type::uninitialized;
-    /// the lexer
-    lexer_t m_lexer;
     /// whether to throw exceptions in case of errors
     const bool allow_exceptions = true;
+    /// a discarded value for the callback
+    BasicJsonType discarded = BasicJsonType::value_t::discarded;
 };
-}  // namespace detail
-}  // namespace nlohmann
-
-// #include <nlohmann/detail/iterators/primitive_iterator.hpp>
-
-
-#include <cstddef> // ptrdiff_t
-#include <limits>  // numeric_limits
-
-namespace nlohmann
-{
-namespace detail
-{
-/*
-@brief an iterator for primitive JSON types
 
-This class models an iterator for primitive JSON types (boolean, number,
-string). It's only purpose is to allow the iterator/const_iterator classes
-to "iterate" over primitive values. Internally, the iterator is modeled by
-a `difference_type` variable. Value begin_value (`0`) models the begin,
-end_value (`1`) models past the end.
-*/
-class primitive_iterator_t
+template<typename BasicJsonType>
+class json_sax_acceptor
 {
-  private:
-    using difference_type = std::ptrdiff_t;
-    static constexpr difference_type begin_value = 0;
-    static constexpr difference_type end_value = begin_value + 1;
-
-    /// iterator as signed integer type
-    difference_type m_it = (std::numeric_limits<std::ptrdiff_t>::min)();
-
   public:
-    constexpr difference_type get_value() const noexcept
-    {
-        return m_it;
-    }
-
-    /// set iterator to a defined beginning
-    void set_begin() noexcept
-    {
-        m_it = begin_value;
-    }
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using string_t = typename BasicJsonType::string_t;
+    using binary_t = typename BasicJsonType::binary_t;
 
-    /// set iterator to a defined past the end
-    void set_end() noexcept
+    bool null()
     {
-        m_it = end_value;
+        return true;
     }
 
-    /// return whether the iterator can be dereferenced
-    constexpr bool is_begin() const noexcept
+    bool boolean(bool /*unused*/)
     {
-        return m_it == begin_value;
+        return true;
     }
 
-    /// return whether the iterator is at end
-    constexpr bool is_end() const noexcept
+    bool number_integer(number_integer_t /*unused*/)
     {
-        return m_it == end_value;
+        return true;
     }
 
-    friend constexpr bool operator==(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    bool number_unsigned(number_unsigned_t /*unused*/)
     {
-        return lhs.m_it == rhs.m_it;
+        return true;
     }
 
-    friend constexpr bool operator<(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    bool number_float(number_float_t /*unused*/, const string_t& /*unused*/)
     {
-        return lhs.m_it < rhs.m_it;
+        return true;
     }
 
-    primitive_iterator_t operator+(difference_type n) noexcept
+    bool string(string_t& /*unused*/)
     {
-        auto result = *this;
-        result += n;
-        return result;
+        return true;
     }
 
-    friend constexpr difference_type operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    bool binary(binary_t& /*unused*/)
     {
-        return lhs.m_it - rhs.m_it;
+        return true;
     }
 
-    primitive_iterator_t& operator++() noexcept
+    bool start_object(std::size_t /*unused*/ = std::size_t(-1))
     {
-        ++m_it;
-        return *this;
+        return true;
     }
 
-    primitive_iterator_t const operator++(int) noexcept
+    bool key(string_t& /*unused*/)
     {
-        auto result = *this;
-        ++m_it;
-        return result;
+        return true;
     }
 
-    primitive_iterator_t& operator--() noexcept
+    bool end_object()
     {
-        --m_it;
-        return *this;
+        return true;
     }
 
-    primitive_iterator_t const operator--(int) noexcept
+    bool start_array(std::size_t /*unused*/ = std::size_t(-1))
     {
-        auto result = *this;
-        --m_it;
-        return result;
+        return true;
     }
 
-    primitive_iterator_t& operator+=(difference_type n) noexcept
+    bool end_array()
     {
-        m_it += n;
-        return *this;
+        return true;
     }
 
-    primitive_iterator_t& operator-=(difference_type n) noexcept
+    bool parse_error(std::size_t /*unused*/, const std::string& /*unused*/, const detail::exception& /*unused*/)
     {
-        m_it -= n;
-        return *this;
+        return false;
     }
 };
 }  // namespace detail
+
 }  // namespace nlohmann
 
-// #include <nlohmann/detail/iterators/internal_iterator.hpp>
+// #include <nlohmann/detail/input/lexer.hpp>
 
 
-// #include <nlohmann/detail/iterators/primitive_iterator.hpp>
+#include <array> // array
+#include <clocale> // localeconv
+#include <cstddef> // size_t
+#include <cstdio> // snprintf
+#include <cstdlib> // strtof, strtod, strtold, strtoll, strtoull
+#include <initializer_list> // initializer_list
+#include <string> // char_traits, string
+#include <utility> // move
+#include <vector> // vector
+
+// #include <nlohmann/detail/input/input_adapters.hpp>
+
+// #include <nlohmann/detail/input/position_t.hpp>
+
+// #include <nlohmann/detail/macro_scope.hpp>
 
 
 namespace nlohmann
 {
 namespace detail
 {
-/*!
-@brief an iterator value
-
-@note This structure could easily be a union, but MSVC currently does not allow
-unions members with complex constructors, see https://github.com/nlohmann/json/pull/105.
-*/
-template<typename BasicJsonType> struct internal_iterator
+///////////
+// lexer //
+///////////
+
+template<typename BasicJsonType>
+class lexer_base
 {
-    /// iterator for JSON objects
-    typename BasicJsonType::object_t::iterator object_iterator {};
-    /// iterator for JSON arrays
-    typename BasicJsonType::array_t::iterator array_iterator {};
-    /// generic iterator for all other types
-    primitive_iterator_t primitive_iterator {};
+  public:
+    /// token types for the parser
+    enum class token_type
+    {
+        uninitialized,    ///< indicating the scanner is uninitialized
+        literal_true,     ///< the `true` literal
+        literal_false,    ///< the `false` literal
+        literal_null,     ///< the `null` literal
+        value_string,     ///< a string -- use get_string() for actual value
+        value_unsigned,   ///< an unsigned integer -- use get_number_unsigned() for actual value
+        value_integer,    ///< a signed integer -- use get_number_integer() for actual value
+        value_float,      ///< an floating point number -- use get_number_float() for actual value
+        begin_array,      ///< the character for array begin `[`
+        begin_object,     ///< the character for object begin `{`
+        end_array,        ///< the character for array end `]`
+        end_object,       ///< the character for object end `}`
+        name_separator,   ///< the name separator `:`
+        value_separator,  ///< the value separator `,`
+        parse_error,      ///< indicating a parse error
+        end_of_input,     ///< indicating the end of the input buffer
+        literal_or_value  ///< a literal or the begin of a value (only for diagnostics)
+    };
+
+    /// return name of values of type token_type (only used for errors)
+    JSON_HEDLEY_RETURNS_NON_NULL
+    JSON_HEDLEY_CONST
+    static const char* token_type_name(const token_type t) noexcept
+    {
+        switch (t)
+        {
+            case token_type::uninitialized:
+                return "<uninitialized>";
+            case token_type::literal_true:
+                return "true literal";
+            case token_type::literal_false:
+                return "false literal";
+            case token_type::literal_null:
+                return "null literal";
+            case token_type::value_string:
+                return "string literal";
+            case token_type::value_unsigned:
+            case token_type::value_integer:
+            case token_type::value_float:
+                return "number literal";
+            case token_type::begin_array:
+                return "'['";
+            case token_type::begin_object:
+                return "'{'";
+            case token_type::end_array:
+                return "']'";
+            case token_type::end_object:
+                return "'}'";
+            case token_type::name_separator:
+                return "':'";
+            case token_type::value_separator:
+                return "','";
+            case token_type::parse_error:
+                return "<parse error>";
+            case token_type::end_of_input:
+                return "end of input";
+            case token_type::literal_or_value:
+                return "'[', '{', or a literal";
+            // LCOV_EXCL_START
+            default: // catch non-enum values
+                return "unknown token";
+                // LCOV_EXCL_STOP
+        }
+    }
 };
-}  // namespace detail
-}  // namespace nlohmann
+/*!
+@brief lexical analysis
 
-// #include <nlohmann/detail/iterators/iter_impl.hpp>
+This class organizes the lexical analysis during JSON deserialization.
+*/
+template<typename BasicJsonType, typename InputAdapterType>
+class lexer : public lexer_base<BasicJsonType>
+{
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using string_t = typename BasicJsonType::string_t;
+    using char_type = typename InputAdapterType::char_type;
+    using char_int_type = typename std::char_traits<char_type>::int_type;
+
+  public:
+    using token_type = typename lexer_base<BasicJsonType>::token_type;
+
+    explicit lexer(InputAdapterType&& adapter, bool ignore_comments_ = false) noexcept
+        : ia(std::move(adapter))
+        , ignore_comments(ignore_comments_)
+        , decimal_point_char(static_cast<char_int_type>(get_decimal_point()))
+    {}
+
+    // delete because of pointer members
+    lexer(const lexer&) = delete;
+    lexer(lexer&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
+    lexer& operator=(lexer&) = delete;
+    lexer& operator=(lexer&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
+    ~lexer() = default;
+
+  private:
+    /////////////////////
+    // locales
+    /////////////////////
+
+    /// return the locale-dependent decimal point
+    JSON_HEDLEY_PURE
+    static char get_decimal_point() noexcept
+    {
+        const auto* loc = localeconv();
+        JSON_ASSERT(loc != nullptr);
+        return (loc->decimal_point == nullptr) ? '.' : *(loc->decimal_point);
+    }
+
+    /////////////////////
+    // scan functions
+    /////////////////////
+
+    /*!
+    @brief get codepoint from 4 hex characters following `\u`
+
+    For input "\u c1 c2 c3 c4" the codepoint is:
+      (c1 * 0x1000) + (c2 * 0x0100) + (c3 * 0x0010) + c4
+    = (c1 << 12) + (c2 << 8) + (c3 << 4) + (c4 << 0)
+
+    Furthermore, the possible characters '0'..'9', 'A'..'F', and 'a'..'f'
+    must be converted to the integers 0x0..0x9, 0xA..0xF, 0xA..0xF, resp. The
+    conversion is done by subtracting the offset (0x30, 0x37, and 0x57)
+    between the ASCII value of the character and the desired integer value.
+
+    @return codepoint (0x0000..0xFFFF) or -1 in case of an error (e.g. EOF or
+            non-hex character)
+    */
+    int get_codepoint()
+    {
+        // this function only makes sense after reading `\u`
+        JSON_ASSERT(current == 'u');
+        int codepoint = 0;
+
+        const auto factors = { 12u, 8u, 4u, 0u };
+        for (const auto factor : factors)
+        {
+            get();
+
+            if (current >= '0' && current <= '9')
+            {
+                codepoint += static_cast<int>((static_cast<unsigned int>(current) - 0x30u) << factor);
+            }
+            else if (current >= 'A' && current <= 'F')
+            {
+                codepoint += static_cast<int>((static_cast<unsigned int>(current) - 0x37u) << factor);
+            }
+            else if (current >= 'a' && current <= 'f')
+            {
+                codepoint += static_cast<int>((static_cast<unsigned int>(current) - 0x57u) << factor);
+            }
+            else
+            {
+                return -1;
+            }
+        }
+
+        JSON_ASSERT(0x0000 <= codepoint && codepoint <= 0xFFFF);
+        return codepoint;
+    }
+
+    /*!
+    @brief check if the next byte(s) are inside a given range
+
+    Adds the current byte and, for each passed range, reads a new byte and
+    checks if it is inside the range. If a violation was detected, set up an
+    error message and return false. Otherwise, return true.
+
+    @param[in] ranges  list of integers; interpreted as list of pairs of
+                       inclusive lower and upper bound, respectively
+
+    @pre The passed list @a ranges must have 2, 4, or 6 elements; that is,
+         1, 2, or 3 pairs. This precondition is enforced by an assertion.
+
+    @return true if and only if no range violation was detected
+    */
+    bool next_byte_in_range(std::initializer_list<char_int_type> ranges)
+    {
+        JSON_ASSERT(ranges.size() == 2 || ranges.size() == 4 || ranges.size() == 6);
+        add(current);
+
+        for (auto range = ranges.begin(); range != ranges.end(); ++range)
+        {
+            get();
+            if (JSON_HEDLEY_LIKELY(*range <= current && current <= *(++range)))
+            {
+                add(current);
+            }
+            else
+            {
+                error_message = "invalid string: ill-formed UTF-8 byte";
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /*!
+    @brief scan a string literal
+
+    This function scans a string according to Sect. 7 of RFC 8259. While
+    scanning, bytes are escaped and copied into buffer token_buffer. Then the
+    function returns successfully, token_buffer is *not* null-terminated (as it
+    may contain \0 bytes), and token_buffer.size() is the number of bytes in the
+    string.
+
+    @return token_type::value_string if string could be successfully scanned,
+            token_type::parse_error otherwise
+
+    @note In case of errors, variable error_message contains a textual
+          description.
+    */
+    token_type scan_string()
+    {
+        // reset token_buffer (ignore opening quote)
+        reset();
+
+        // we entered the function by reading an open quote
+        JSON_ASSERT(current == '\"');
+
+        while (true)
+        {
+            // get next character
+            switch (get())
+            {
+                // end of file while parsing string
+                case std::char_traits<char_type>::eof():
+                {
+                    error_message = "invalid string: missing closing quote";
+                    return token_type::parse_error;
+                }
+
+                // closing quote
+                case '\"':
+                {
+                    return token_type::value_string;
+                }
 
+                // escapes
+                case '\\':
+                {
+                    switch (get())
+                    {
+                        // quotation mark
+                        case '\"':
+                            add('\"');
+                            break;
+                        // reverse solidus
+                        case '\\':
+                            add('\\');
+                            break;
+                        // solidus
+                        case '/':
+                            add('/');
+                            break;
+                        // backspace
+                        case 'b':
+                            add('\b');
+                            break;
+                        // form feed
+                        case 'f':
+                            add('\f');
+                            break;
+                        // line feed
+                        case 'n':
+                            add('\n');
+                            break;
+                        // carriage return
+                        case 'r':
+                            add('\r');
+                            break;
+                        // tab
+                        case 't':
+                            add('\t');
+                            break;
+
+                        // unicode escapes
+                        case 'u':
+                        {
+                            const int codepoint1 = get_codepoint();
+                            int codepoint = codepoint1; // start with codepoint1
+
+                            if (JSON_HEDLEY_UNLIKELY(codepoint1 == -1))
+                            {
+                                error_message = "invalid string: '\\u' must be followed by 4 hex digits";
+                                return token_type::parse_error;
+                            }
+
+                            // check if code point is a high surrogate
+                            if (0xD800 <= codepoint1 && codepoint1 <= 0xDBFF)
+                            {
+                                // expect next \uxxxx entry
+                                if (JSON_HEDLEY_LIKELY(get() == '\\' && get() == 'u'))
+                                {
+                                    const int codepoint2 = get_codepoint();
+
+                                    if (JSON_HEDLEY_UNLIKELY(codepoint2 == -1))
+                                    {
+                                        error_message = "invalid string: '\\u' must be followed by 4 hex digits";
+                                        return token_type::parse_error;
+                                    }
+
+                                    // check if codepoint2 is a low surrogate
+                                    if (JSON_HEDLEY_LIKELY(0xDC00 <= codepoint2 && codepoint2 <= 0xDFFF))
+                                    {
+                                        // overwrite codepoint
+                                        codepoint = static_cast<int>(
+                                                        // high surrogate occupies the most significant 22 bits
+                                                        (static_cast<unsigned int>(codepoint1) << 10u)
+                                                        // low surrogate occupies the least significant 15 bits
+                                                        + static_cast<unsigned int>(codepoint2)
+                                                        // there is still the 0xD800, 0xDC00 and 0x10000 noise
+                                                        // in the result so we have to subtract with:
+                                                        // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00
+                                                        - 0x35FDC00u);
+                                    }
+                                    else
+                                    {
+                                        error_message = "invalid string: surrogate U+D800..U+DBFF must be followed by U+DC00..U+DFFF";
+                                        return token_type::parse_error;
+                                    }
+                                }
+                                else
+                                {
+                                    error_message = "invalid string: surrogate U+D800..U+DBFF must be followed by U+DC00..U+DFFF";
+                                    return token_type::parse_error;
+                                }
+                            }
+                            else
+                            {
+                                if (JSON_HEDLEY_UNLIKELY(0xDC00 <= codepoint1 && codepoint1 <= 0xDFFF))
+                                {
+                                    error_message = "invalid string: surrogate U+DC00..U+DFFF must follow U+D800..U+DBFF";
+                                    return token_type::parse_error;
+                                }
+                            }
+
+                            // result of the above calculation yields a proper codepoint
+                            JSON_ASSERT(0x00 <= codepoint && codepoint <= 0x10FFFF);
+
+                            // translate codepoint into bytes
+                            if (codepoint < 0x80)
+                            {
+                                // 1-byte characters: 0xxxxxxx (ASCII)
+                                add(static_cast<char_int_type>(codepoint));
+                            }
+                            else if (codepoint <= 0x7FF)
+                            {
+                                // 2-byte characters: 110xxxxx 10xxxxxx
+                                add(static_cast<char_int_type>(0xC0u | (static_cast<unsigned int>(codepoint) >> 6u)));
+                                add(static_cast<char_int_type>(0x80u | (static_cast<unsigned int>(codepoint) & 0x3Fu)));
+                            }
+                            else if (codepoint <= 0xFFFF)
+                            {
+                                // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx
+                                add(static_cast<char_int_type>(0xE0u | (static_cast<unsigned int>(codepoint) >> 12u)));
+                                add(static_cast<char_int_type>(0x80u | ((static_cast<unsigned int>(codepoint) >> 6u) & 0x3Fu)));
+                                add(static_cast<char_int_type>(0x80u | (static_cast<unsigned int>(codepoint) & 0x3Fu)));
+                            }
+                            else
+                            {
+                                // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+                                add(static_cast<char_int_type>(0xF0u | (static_cast<unsigned int>(codepoint) >> 18u)));
+                                add(static_cast<char_int_type>(0x80u | ((static_cast<unsigned int>(codepoint) >> 12u) & 0x3Fu)));
+                                add(static_cast<char_int_type>(0x80u | ((static_cast<unsigned int>(codepoint) >> 6u) & 0x3Fu)));
+                                add(static_cast<char_int_type>(0x80u | (static_cast<unsigned int>(codepoint) & 0x3Fu)));
+                            }
+
+                            break;
+                        }
+
+                        // other characters after escape
+                        default:
+                            error_message = "invalid string: forbidden character after backslash";
+                            return token_type::parse_error;
+                    }
+
+                    break;
+                }
+
+                // invalid control characters
+                case 0x00:
+                {
+                    error_message = "invalid string: control character U+0000 (NUL) must be escaped to \\u0000";
+                    return token_type::parse_error;
+                }
+
+                case 0x01:
+                {
+                    error_message = "invalid string: control character U+0001 (SOH) must be escaped to \\u0001";
+                    return token_type::parse_error;
+                }
+
+                case 0x02:
+                {
+                    error_message = "invalid string: control character U+0002 (STX) must be escaped to \\u0002";
+                    return token_type::parse_error;
+                }
+
+                case 0x03:
+                {
+                    error_message = "invalid string: control character U+0003 (ETX) must be escaped to \\u0003";
+                    return token_type::parse_error;
+                }
+
+                case 0x04:
+                {
+                    error_message = "invalid string: control character U+0004 (EOT) must be escaped to \\u0004";
+                    return token_type::parse_error;
+                }
+
+                case 0x05:
+                {
+                    error_message = "invalid string: control character U+0005 (ENQ) must be escaped to \\u0005";
+                    return token_type::parse_error;
+                }
+
+                case 0x06:
+                {
+                    error_message = "invalid string: control character U+0006 (ACK) must be escaped to \\u0006";
+                    return token_type::parse_error;
+                }
+
+                case 0x07:
+                {
+                    error_message = "invalid string: control character U+0007 (BEL) must be escaped to \\u0007";
+                    return token_type::parse_error;
+                }
+
+                case 0x08:
+                {
+                    error_message = "invalid string: control character U+0008 (BS) must be escaped to \\u0008 or \\b";
+                    return token_type::parse_error;
+                }
+
+                case 0x09:
+                {
+                    error_message = "invalid string: control character U+0009 (HT) must be escaped to \\u0009 or \\t";
+                    return token_type::parse_error;
+                }
+
+                case 0x0A:
+                {
+                    error_message = "invalid string: control character U+000A (LF) must be escaped to \\u000A or \\n";
+                    return token_type::parse_error;
+                }
+
+                case 0x0B:
+                {
+                    error_message = "invalid string: control character U+000B (VT) must be escaped to \\u000B";
+                    return token_type::parse_error;
+                }
+
+                case 0x0C:
+                {
+                    error_message = "invalid string: control character U+000C (FF) must be escaped to \\u000C or \\f";
+                    return token_type::parse_error;
+                }
+
+                case 0x0D:
+                {
+                    error_message = "invalid string: control character U+000D (CR) must be escaped to \\u000D or \\r";
+                    return token_type::parse_error;
+                }
+
+                case 0x0E:
+                {
+                    error_message = "invalid string: control character U+000E (SO) must be escaped to \\u000E";
+                    return token_type::parse_error;
+                }
+
+                case 0x0F:
+                {
+                    error_message = "invalid string: control character U+000F (SI) must be escaped to \\u000F";
+                    return token_type::parse_error;
+                }
+
+                case 0x10:
+                {
+                    error_message = "invalid string: control character U+0010 (DLE) must be escaped to \\u0010";
+                    return token_type::parse_error;
+                }
+
+                case 0x11:
+                {
+                    error_message = "invalid string: control character U+0011 (DC1) must be escaped to \\u0011";
+                    return token_type::parse_error;
+                }
+
+                case 0x12:
+                {
+                    error_message = "invalid string: control character U+0012 (DC2) must be escaped to \\u0012";
+                    return token_type::parse_error;
+                }
+
+                case 0x13:
+                {
+                    error_message = "invalid string: control character U+0013 (DC3) must be escaped to \\u0013";
+                    return token_type::parse_error;
+                }
+
+                case 0x14:
+                {
+                    error_message = "invalid string: control character U+0014 (DC4) must be escaped to \\u0014";
+                    return token_type::parse_error;
+                }
+
+                case 0x15:
+                {
+                    error_message = "invalid string: control character U+0015 (NAK) must be escaped to \\u0015";
+                    return token_type::parse_error;
+                }
+
+                case 0x16:
+                {
+                    error_message = "invalid string: control character U+0016 (SYN) must be escaped to \\u0016";
+                    return token_type::parse_error;
+                }
+
+                case 0x17:
+                {
+                    error_message = "invalid string: control character U+0017 (ETB) must be escaped to \\u0017";
+                    return token_type::parse_error;
+                }
+
+                case 0x18:
+                {
+                    error_message = "invalid string: control character U+0018 (CAN) must be escaped to \\u0018";
+                    return token_type::parse_error;
+                }
+
+                case 0x19:
+                {
+                    error_message = "invalid string: control character U+0019 (EM) must be escaped to \\u0019";
+                    return token_type::parse_error;
+                }
+
+                case 0x1A:
+                {
+                    error_message = "invalid string: control character U+001A (SUB) must be escaped to \\u001A";
+                    return token_type::parse_error;
+                }
+
+                case 0x1B:
+                {
+                    error_message = "invalid string: control character U+001B (ESC) must be escaped to \\u001B";
+                    return token_type::parse_error;
+                }
+
+                case 0x1C:
+                {
+                    error_message = "invalid string: control character U+001C (FS) must be escaped to \\u001C";
+                    return token_type::parse_error;
+                }
+
+                case 0x1D:
+                {
+                    error_message = "invalid string: control character U+001D (GS) must be escaped to \\u001D";
+                    return token_type::parse_error;
+                }
+
+                case 0x1E:
+                {
+                    error_message = "invalid string: control character U+001E (RS) must be escaped to \\u001E";
+                    return token_type::parse_error;
+                }
+
+                case 0x1F:
+                {
+                    error_message = "invalid string: control character U+001F (US) must be escaped to \\u001F";
+                    return token_type::parse_error;
+                }
+
+                // U+0020..U+007F (except U+0022 (quote) and U+005C (backspace))
+                case 0x20:
+                case 0x21:
+                case 0x23:
+                case 0x24:
+                case 0x25:
+                case 0x26:
+                case 0x27:
+                case 0x28:
+                case 0x29:
+                case 0x2A:
+                case 0x2B:
+                case 0x2C:
+                case 0x2D:
+                case 0x2E:
+                case 0x2F:
+                case 0x30:
+                case 0x31:
+                case 0x32:
+                case 0x33:
+                case 0x34:
+                case 0x35:
+                case 0x36:
+                case 0x37:
+                case 0x38:
+                case 0x39:
+                case 0x3A:
+                case 0x3B:
+                case 0x3C:
+                case 0x3D:
+                case 0x3E:
+                case 0x3F:
+                case 0x40:
+                case 0x41:
+                case 0x42:
+                case 0x43:
+                case 0x44:
+                case 0x45:
+                case 0x46:
+                case 0x47:
+                case 0x48:
+                case 0x49:
+                case 0x4A:
+                case 0x4B:
+                case 0x4C:
+                case 0x4D:
+                case 0x4E:
+                case 0x4F:
+                case 0x50:
+                case 0x51:
+                case 0x52:
+                case 0x53:
+                case 0x54:
+                case 0x55:
+                case 0x56:
+                case 0x57:
+                case 0x58:
+                case 0x59:
+                case 0x5A:
+                case 0x5B:
+                case 0x5D:
+                case 0x5E:
+                case 0x5F:
+                case 0x60:
+                case 0x61:
+                case 0x62:
+                case 0x63:
+                case 0x64:
+                case 0x65:
+                case 0x66:
+                case 0x67:
+                case 0x68:
+                case 0x69:
+                case 0x6A:
+                case 0x6B:
+                case 0x6C:
+                case 0x6D:
+                case 0x6E:
+                case 0x6F:
+                case 0x70:
+                case 0x71:
+                case 0x72:
+                case 0x73:
+                case 0x74:
+                case 0x75:
+                case 0x76:
+                case 0x77:
+                case 0x78:
+                case 0x79:
+                case 0x7A:
+                case 0x7B:
+                case 0x7C:
+                case 0x7D:
+                case 0x7E:
+                case 0x7F:
+                {
+                    add(current);
+                    break;
+                }
+
+                // U+0080..U+07FF: bytes C2..DF 80..BF
+                case 0xC2:
+                case 0xC3:
+                case 0xC4:
+                case 0xC5:
+                case 0xC6:
+                case 0xC7:
+                case 0xC8:
+                case 0xC9:
+                case 0xCA:
+                case 0xCB:
+                case 0xCC:
+                case 0xCD:
+                case 0xCE:
+                case 0xCF:
+                case 0xD0:
+                case 0xD1:
+                case 0xD2:
+                case 0xD3:
+                case 0xD4:
+                case 0xD5:
+                case 0xD6:
+                case 0xD7:
+                case 0xD8:
+                case 0xD9:
+                case 0xDA:
+                case 0xDB:
+                case 0xDC:
+                case 0xDD:
+                case 0xDE:
+                case 0xDF:
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!next_byte_in_range({0x80, 0xBF})))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
+
+                // U+0800..U+0FFF: bytes E0 A0..BF 80..BF
+                case 0xE0:
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!(next_byte_in_range({0xA0, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
+
+                // U+1000..U+CFFF: bytes E1..EC 80..BF 80..BF
+                // U+E000..U+FFFF: bytes EE..EF 80..BF 80..BF
+                case 0xE1:
+                case 0xE2:
+                case 0xE3:
+                case 0xE4:
+                case 0xE5:
+                case 0xE6:
+                case 0xE7:
+                case 0xE8:
+                case 0xE9:
+                case 0xEA:
+                case 0xEB:
+                case 0xEC:
+                case 0xEE:
+                case 0xEF:
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!(next_byte_in_range({0x80, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
+
+                // U+D000..U+D7FF: bytes ED 80..9F 80..BF
+                case 0xED:
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!(next_byte_in_range({0x80, 0x9F, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
+
+                // U+10000..U+3FFFF F0 90..BF 80..BF 80..BF
+                case 0xF0:
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!(next_byte_in_range({0x90, 0xBF, 0x80, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
+
+                // U+40000..U+FFFFF F1..F3 80..BF 80..BF 80..BF
+                case 0xF1:
+                case 0xF2:
+                case 0xF3:
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!(next_byte_in_range({0x80, 0xBF, 0x80, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
+
+                // U+100000..U+10FFFF F4 80..8F 80..BF 80..BF
+                case 0xF4:
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!(next_byte_in_range({0x80, 0x8F, 0x80, 0xBF, 0x80, 0xBF}))))
+                    {
+                        return token_type::parse_error;
+                    }
+                    break;
+                }
+
+                // remaining bytes (80..C1 and F5..FF) are ill-formed
+                default:
+                {
+                    error_message = "invalid string: ill-formed UTF-8 byte";
+                    return token_type::parse_error;
+                }
+            }
+        }
+    }
+
+    /*!
+     * @brief scan a comment
+     * @return whether comment could be scanned successfully
+     */
+    bool scan_comment()
+    {
+        switch (get())
+        {
+            // single-line comments skip input until a newline or EOF is read
+            case '/':
+            {
+                while (true)
+                {
+                    switch (get())
+                    {
+                        case '\n':
+                        case '\r':
+                        case std::char_traits<char_type>::eof():
+                        case '\0':
+                            return true;
+
+                        default:
+                            break;
+                    }
+                }
+            }
+
+            // multi-line comments skip input until */ is read
+            case '*':
+            {
+                while (true)
+                {
+                    switch (get())
+                    {
+                        case std::char_traits<char_type>::eof():
+                        case '\0':
+                        {
+                            error_message = "invalid comment; missing closing '*/'";
+                            return false;
+                        }
+
+                        case '*':
+                        {
+                            switch (get())
+                            {
+                                case '/':
+                                    return true;
+
+                                default:
+                                {
+                                    unget();
+                                    continue;
+                                }
+                            }
+                        }
+
+                        default:
+                            continue;
+                    }
+                }
+            }
+
+            // unexpected character after reading '/'
+            default:
+            {
+                error_message = "invalid comment; expecting '/' or '*' after '/'";
+                return false;
+            }
+        }
+    }
+
+    JSON_HEDLEY_NON_NULL(2)
+    static void strtof(float& f, const char* str, char** endptr) noexcept
+    {
+        f = std::strtof(str, endptr);
+    }
+
+    JSON_HEDLEY_NON_NULL(2)
+    static void strtof(double& f, const char* str, char** endptr) noexcept
+    {
+        f = std::strtod(str, endptr);
+    }
+
+    JSON_HEDLEY_NON_NULL(2)
+    static void strtof(long double& f, const char* str, char** endptr) noexcept
+    {
+        f = std::strtold(str, endptr);
+    }
+
+    /*!
+    @brief scan a number literal
+
+    This function scans a string according to Sect. 6 of RFC 8259.
+
+    The function is realized with a deterministic finite state machine derived
+    from the grammar described in RFC 8259. Starting in state "init", the
+    input is read and used to determined the next state. Only state "done"
+    accepts the number. State "error" is a trap state to model errors. In the
+    table below, "anything" means any character but the ones listed before.
+
+    state    | 0        | 1-9      | e E      | +       | -       | .        | anything
+    ---------|----------|----------|----------|---------|---------|----------|-----------
+    init     | zero     | any1     | [error]  | [error] | minus   | [error]  | [error]
+    minus    | zero     | any1     | [error]  | [error] | [error] | [error]  | [error]
+    zero     | done     | done     | exponent | done    | done    | decimal1 | done
+    any1     | any1     | any1     | exponent | done    | done    | decimal1 | done
+    decimal1 | decimal2 | decimal2 | [error]  | [error] | [error] | [error]  | [error]
+    decimal2 | decimal2 | decimal2 | exponent | done    | done    | done     | done
+    exponent | any2     | any2     | [error]  | sign    | sign    | [error]  | [error]
+    sign     | any2     | any2     | [error]  | [error] | [error] | [error]  | [error]
+    any2     | any2     | any2     | done     | done    | done    | done     | done
+
+    The state machine is realized with one label per state (prefixed with
+    "scan_number_") and `goto` statements between them. The state machine
+    contains cycles, but any cycle can be left when EOF is read. Therefore,
+    the function is guaranteed to terminate.
+
+    During scanning, the read bytes are stored in token_buffer. This string is
+    then converted to a signed integer, an unsigned integer, or a
+    floating-point number.
+
+    @return token_type::value_unsigned, token_type::value_integer, or
+            token_type::value_float if number could be successfully scanned,
+            token_type::parse_error otherwise
+
+    @note The scanner is independent of the current locale. Internally, the
+          locale's decimal point is used instead of `.` to work with the
+          locale-dependent converters.
+    */
+    token_type scan_number()  // lgtm [cpp/use-of-goto]
+    {
+        // reset token_buffer to store the number's bytes
+        reset();
+
+        // the type of the parsed number; initially set to unsigned; will be
+        // changed if minus sign, decimal point or exponent is read
+        token_type number_type = token_type::value_unsigned;
+
+        // state (init): we just found out we need to scan a number
+        switch (current)
+        {
+            case '-':
+            {
+                add(current);
+                goto scan_number_minus;
+            }
+
+            case '0':
+            {
+                add(current);
+                goto scan_number_zero;
+            }
+
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any1;
+            }
+
+            // all other characters are rejected outside scan_number()
+            default:            // LCOV_EXCL_LINE
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+        }
+
+scan_number_minus:
+        // state: we just parsed a leading minus sign
+        number_type = token_type::value_integer;
+        switch (get())
+        {
+            case '0':
+            {
+                add(current);
+                goto scan_number_zero;
+            }
+
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any1;
+            }
+
+            default:
+            {
+                error_message = "invalid number; expected digit after '-'";
+                return token_type::parse_error;
+            }
+        }
+
+scan_number_zero:
+        // state: we just parse a zero (maybe with a leading minus sign)
+        switch (get())
+        {
+            case '.':
+            {
+                add(decimal_point_char);
+                goto scan_number_decimal1;
+            }
+
+            case 'e':
+            case 'E':
+            {
+                add(current);
+                goto scan_number_exponent;
+            }
+
+            default:
+                goto scan_number_done;
+        }
+
+scan_number_any1:
+        // state: we just parsed a number 0-9 (maybe with a leading minus sign)
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any1;
+            }
+
+            case '.':
+            {
+                add(decimal_point_char);
+                goto scan_number_decimal1;
+            }
+
+            case 'e':
+            case 'E':
+            {
+                add(current);
+                goto scan_number_exponent;
+            }
+
+            default:
+                goto scan_number_done;
+        }
+
+scan_number_decimal1:
+        // state: we just parsed a decimal point
+        number_type = token_type::value_float;
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_decimal2;
+            }
+
+            default:
+            {
+                error_message = "invalid number; expected digit after '.'";
+                return token_type::parse_error;
+            }
+        }
+
+scan_number_decimal2:
+        // we just parsed at least one number after a decimal point
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_decimal2;
+            }
+
+            case 'e':
+            case 'E':
+            {
+                add(current);
+                goto scan_number_exponent;
+            }
+
+            default:
+                goto scan_number_done;
+        }
+
+scan_number_exponent:
+        // we just parsed an exponent
+        number_type = token_type::value_float;
+        switch (get())
+        {
+            case '+':
+            case '-':
+            {
+                add(current);
+                goto scan_number_sign;
+            }
+
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any2;
+            }
+
+            default:
+            {
+                error_message =
+                    "invalid number; expected '+', '-', or digit after exponent";
+                return token_type::parse_error;
+            }
+        }
+
+scan_number_sign:
+        // we just parsed an exponent sign
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any2;
+            }
+
+            default:
+            {
+                error_message = "invalid number; expected digit after exponent sign";
+                return token_type::parse_error;
+            }
+        }
+
+scan_number_any2:
+        // we just parsed a number after the exponent or exponent sign
+        switch (get())
+        {
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+            {
+                add(current);
+                goto scan_number_any2;
+            }
+
+            default:
+                goto scan_number_done;
+        }
+
+scan_number_done:
+        // unget the character after the number (we only read it to know that
+        // we are done scanning a number)
+        unget();
+
+        char* endptr = nullptr; // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        errno = 0;
+
+        // try to parse integers first and fall back to floats
+        if (number_type == token_type::value_unsigned)
+        {
+            const auto x = std::strtoull(token_buffer.data(), &endptr, 10);
+
+            // we checked the number format before
+            JSON_ASSERT(endptr == token_buffer.data() + token_buffer.size());
+
+            if (errno == 0)
+            {
+                value_unsigned = static_cast<number_unsigned_t>(x);
+                if (value_unsigned == x)
+                {
+                    return token_type::value_unsigned;
+                }
+            }
+        }
+        else if (number_type == token_type::value_integer)
+        {
+            const auto x = std::strtoll(token_buffer.data(), &endptr, 10);
+
+            // we checked the number format before
+            JSON_ASSERT(endptr == token_buffer.data() + token_buffer.size());
+
+            if (errno == 0)
+            {
+                value_integer = static_cast<number_integer_t>(x);
+                if (value_integer == x)
+                {
+                    return token_type::value_integer;
+                }
+            }
+        }
+
+        // this code is reached if we parse a floating-point number or if an
+        // integer conversion above failed
+        strtof(value_float, token_buffer.data(), &endptr);
+
+        // we checked the number format before
+        JSON_ASSERT(endptr == token_buffer.data() + token_buffer.size());
+
+        return token_type::value_float;
+    }
+
+    /*!
+    @param[in] literal_text  the literal text to expect
+    @param[in] length        the length of the passed literal text
+    @param[in] return_type   the token type to return on success
+    */
+    JSON_HEDLEY_NON_NULL(2)
+    token_type scan_literal(const char_type* literal_text, const std::size_t length,
+                            token_type return_type)
+    {
+        JSON_ASSERT(std::char_traits<char_type>::to_char_type(current) == literal_text[0]);
+        for (std::size_t i = 1; i < length; ++i)
+        {
+            if (JSON_HEDLEY_UNLIKELY(std::char_traits<char_type>::to_char_type(get()) != literal_text[i]))
+            {
+                error_message = "invalid literal";
+                return token_type::parse_error;
+            }
+        }
+        return return_type;
+    }
+
+    /////////////////////
+    // input management
+    /////////////////////
+
+    /// reset token_buffer; current character is beginning of token
+    void reset() noexcept
+    {
+        token_buffer.clear();
+        token_string.clear();
+        token_string.push_back(std::char_traits<char_type>::to_char_type(current));
+    }
+
+    /*
+    @brief get next character from the input
+
+    This function provides the interface to the used input adapter. It does
+    not throw in case the input reached EOF, but returns a
+    `std::char_traits<char>::eof()` in that case.  Stores the scanned characters
+    for use in error messages.
+
+    @return character read from the input
+    */
+    char_int_type get()
+    {
+        ++position.chars_read_total;
+        ++position.chars_read_current_line;
+
+        if (next_unget)
+        {
+            // just reset the next_unget variable and work with current
+            next_unget = false;
+        }
+        else
+        {
+            current = ia.get_character();
+        }
+
+        if (JSON_HEDLEY_LIKELY(current != std::char_traits<char_type>::eof()))
+        {
+            token_string.push_back(std::char_traits<char_type>::to_char_type(current));
+        }
+
+        if (current == '\n')
+        {
+            ++position.lines_read;
+            position.chars_read_current_line = 0;
+        }
+
+        return current;
+    }
+
+    /*!
+    @brief unget current character (read it again on next get)
+
+    We implement unget by setting variable next_unget to true. The input is not
+    changed - we just simulate ungetting by modifying chars_read_total,
+    chars_read_current_line, and token_string. The next call to get() will
+    behave as if the unget character is read again.
+    */
+    void unget()
+    {
+        next_unget = true;
+
+        --position.chars_read_total;
+
+        // in case we "unget" a newline, we have to also decrement the lines_read
+        if (position.chars_read_current_line == 0)
+        {
+            if (position.lines_read > 0)
+            {
+                --position.lines_read;
+            }
+        }
+        else
+        {
+            --position.chars_read_current_line;
+        }
+
+        if (JSON_HEDLEY_LIKELY(current != std::char_traits<char_type>::eof()))
+        {
+            JSON_ASSERT(!token_string.empty());
+            token_string.pop_back();
+        }
+    }
+
+    /// add a character to token_buffer
+    void add(char_int_type c)
+    {
+        token_buffer.push_back(static_cast<typename string_t::value_type>(c));
+    }
+
+  public:
+    /////////////////////
+    // value getters
+    /////////////////////
+
+    /// return integer value
+    constexpr number_integer_t get_number_integer() const noexcept
+    {
+        return value_integer;
+    }
+
+    /// return unsigned integer value
+    constexpr number_unsigned_t get_number_unsigned() const noexcept
+    {
+        return value_unsigned;
+    }
+
+    /// return floating-point value
+    constexpr number_float_t get_number_float() const noexcept
+    {
+        return value_float;
+    }
+
+    /// return current string value (implicitly resets the token; useful only once)
+    string_t& get_string()
+    {
+        return token_buffer;
+    }
+
+    /////////////////////
+    // diagnostics
+    /////////////////////
+
+    /// return position of last read token
+    constexpr position_t get_position() const noexcept
+    {
+        return position;
+    }
+
+    /// return the last read token (for errors only).  Will never contain EOF
+    /// (an arbitrary value that is not a valid char value, often -1), because
+    /// 255 may legitimately occur.  May contain NUL, which should be escaped.
+    std::string get_token_string() const
+    {
+        // escape control characters
+        std::string result;
+        for (const auto c : token_string)
+        {
+            if (static_cast<unsigned char>(c) <= '\x1F')
+            {
+                // escape control characters
+                std::array<char, 9> cs{{}};
+                (std::snprintf)(cs.data(), cs.size(), "<U+%.4X>", static_cast<unsigned char>(c)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                result += cs.data();
+            }
+            else
+            {
+                // add character as is
+                result.push_back(static_cast<std::string::value_type>(c));
+            }
+        }
+
+        return result;
+    }
+
+    /// return syntax error message
+    JSON_HEDLEY_RETURNS_NON_NULL
+    constexpr const char* get_error_message() const noexcept
+    {
+        return error_message;
+    }
+
+    /////////////////////
+    // actual scanner
+    /////////////////////
+
+    /*!
+    @brief skip the UTF-8 byte order mark
+    @return true iff there is no BOM or the correct BOM has been skipped
+    */
+    bool skip_bom()
+    {
+        if (get() == 0xEF)
+        {
+            // check if we completely parse the BOM
+            return get() == 0xBB && get() == 0xBF;
+        }
+
+        // the first character is not the beginning of the BOM; unget it to
+        // process is later
+        unget();
+        return true;
+    }
+
+    void skip_whitespace()
+    {
+        do
+        {
+            get();
+        }
+        while (current == ' ' || current == '\t' || current == '\n' || current == '\r');
+    }
+
+    token_type scan()
+    {
+        // initially, skip the BOM
+        if (position.chars_read_total == 0 && !skip_bom())
+        {
+            error_message = "invalid BOM; must be 0xEF 0xBB 0xBF if given";
+            return token_type::parse_error;
+        }
+
+        // read next character and ignore whitespace
+        skip_whitespace();
+
+        // ignore comments
+        while (ignore_comments && current == '/')
+        {
+            if (!scan_comment())
+            {
+                return token_type::parse_error;
+            }
+
+            // skip following whitespace
+            skip_whitespace();
+        }
+
+        switch (current)
+        {
+            // structural characters
+            case '[':
+                return token_type::begin_array;
+            case ']':
+                return token_type::end_array;
+            case '{':
+                return token_type::begin_object;
+            case '}':
+                return token_type::end_object;
+            case ':':
+                return token_type::name_separator;
+            case ',':
+                return token_type::value_separator;
+
+            // literals
+            case 't':
+            {
+                std::array<char_type, 4> true_literal = {{char_type('t'), char_type('r'), char_type('u'), char_type('e')}};
+                return scan_literal(true_literal.data(), true_literal.size(), token_type::literal_true);
+            }
+            case 'f':
+            {
+                std::array<char_type, 5> false_literal = {{char_type('f'), char_type('a'), char_type('l'), char_type('s'), char_type('e')}};
+                return scan_literal(false_literal.data(), false_literal.size(), token_type::literal_false);
+            }
+            case 'n':
+            {
+                std::array<char_type, 4> null_literal = {{char_type('n'), char_type('u'), char_type('l'), char_type('l')}};
+                return scan_literal(null_literal.data(), null_literal.size(), token_type::literal_null);
+            }
+
+            // string
+            case '\"':
+                return scan_string();
+
+            // number
+            case '-':
+            case '0':
+            case '1':
+            case '2':
+            case '3':
+            case '4':
+            case '5':
+            case '6':
+            case '7':
+            case '8':
+            case '9':
+                return scan_number();
+
+            // end of input (the null byte is needed when parsing from
+            // string literals)
+            case '\0':
+            case std::char_traits<char_type>::eof():
+                return token_type::end_of_input;
+
+            // error
+            default:
+                error_message = "invalid literal";
+                return token_type::parse_error;
+        }
+    }
+
+  private:
+    /// input adapter
+    InputAdapterType ia;
+
+    /// whether comments should be ignored (true) or signaled as errors (false)
+    const bool ignore_comments = false;
+
+    /// the current character
+    char_int_type current = std::char_traits<char_type>::eof();
+
+    /// whether the next get() call should just return current
+    bool next_unget = false;
+
+    /// the start position of the current token
+    position_t position {};
+
+    /// raw input token string (for error messages)
+    std::vector<char_type> token_string {};
+
+    /// buffer for variable-length tokens (numbers, strings)
+    string_t token_buffer {};
+
+    /// a description of occurred lexer errors
+    const char* error_message = "";
+
+    // number values
+    number_integer_t value_integer = 0;
+    number_unsigned_t value_unsigned = 0;
+    number_float_t value_float = 0;
+
+    /// the decimal point
+    const char_int_type decimal_point_char = '.';
+};
+}  // namespace detail
+}  // namespace nlohmann
+
+// #include <nlohmann/detail/macro_scope.hpp>
+
+// #include <nlohmann/detail/meta/is_sax.hpp>
+
+
+#include <cstdint> // size_t
+#include <utility> // declval
+#include <string> // string
+
+// #include <nlohmann/detail/meta/detected.hpp>
+
+// #include <nlohmann/detail/meta/type_traits.hpp>
+
+
+namespace nlohmann
+{
+namespace detail
+{
+template<typename T>
+using null_function_t = decltype(std::declval<T&>().null());
+
+template<typename T>
+using boolean_function_t =
+    decltype(std::declval<T&>().boolean(std::declval<bool>()));
+
+template<typename T, typename Integer>
+using number_integer_function_t =
+    decltype(std::declval<T&>().number_integer(std::declval<Integer>()));
+
+template<typename T, typename Unsigned>
+using number_unsigned_function_t =
+    decltype(std::declval<T&>().number_unsigned(std::declval<Unsigned>()));
+
+template<typename T, typename Float, typename String>
+using number_float_function_t = decltype(std::declval<T&>().number_float(
+                                    std::declval<Float>(), std::declval<const String&>()));
+
+template<typename T, typename String>
+using string_function_t =
+    decltype(std::declval<T&>().string(std::declval<String&>()));
+
+template<typename T, typename Binary>
+using binary_function_t =
+    decltype(std::declval<T&>().binary(std::declval<Binary&>()));
+
+template<typename T>
+using start_object_function_t =
+    decltype(std::declval<T&>().start_object(std::declval<std::size_t>()));
+
+template<typename T, typename String>
+using key_function_t =
+    decltype(std::declval<T&>().key(std::declval<String&>()));
+
+template<typename T>
+using end_object_function_t = decltype(std::declval<T&>().end_object());
+
+template<typename T>
+using start_array_function_t =
+    decltype(std::declval<T&>().start_array(std::declval<std::size_t>()));
+
+template<typename T>
+using end_array_function_t = decltype(std::declval<T&>().end_array());
+
+template<typename T, typename Exception>
+using parse_error_function_t = decltype(std::declval<T&>().parse_error(
+        std::declval<std::size_t>(), std::declval<const std::string&>(),
+        std::declval<const Exception&>()));
+
+template<typename SAX, typename BasicJsonType>
+struct is_sax
+{
+  private:
+    static_assert(is_basic_json<BasicJsonType>::value,
+                  "BasicJsonType must be of type basic_json<...>");
+
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using string_t = typename BasicJsonType::string_t;
+    using binary_t = typename BasicJsonType::binary_t;
+    using exception_t = typename BasicJsonType::exception;
+
+  public:
+    static constexpr bool value =
+        is_detected_exact<bool, null_function_t, SAX>::value &&
+        is_detected_exact<bool, boolean_function_t, SAX>::value &&
+        is_detected_exact<bool, number_integer_function_t, SAX, number_integer_t>::value &&
+        is_detected_exact<bool, number_unsigned_function_t, SAX, number_unsigned_t>::value &&
+        is_detected_exact<bool, number_float_function_t, SAX, number_float_t, string_t>::value &&
+        is_detected_exact<bool, string_function_t, SAX, string_t>::value &&
+        is_detected_exact<bool, binary_function_t, SAX, binary_t>::value &&
+        is_detected_exact<bool, start_object_function_t, SAX>::value &&
+        is_detected_exact<bool, key_function_t, SAX, string_t>::value &&
+        is_detected_exact<bool, end_object_function_t, SAX>::value &&
+        is_detected_exact<bool, start_array_function_t, SAX>::value &&
+        is_detected_exact<bool, end_array_function_t, SAX>::value &&
+        is_detected_exact<bool, parse_error_function_t, SAX, exception_t>::value;
+};
+
+template<typename SAX, typename BasicJsonType>
+struct is_sax_static_asserts
+{
+  private:
+    static_assert(is_basic_json<BasicJsonType>::value,
+                  "BasicJsonType must be of type basic_json<...>");
+
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using string_t = typename BasicJsonType::string_t;
+    using binary_t = typename BasicJsonType::binary_t;
+    using exception_t = typename BasicJsonType::exception;
+
+  public:
+    static_assert(is_detected_exact<bool, null_function_t, SAX>::value,
+                  "Missing/invalid function: bool null()");
+    static_assert(is_detected_exact<bool, boolean_function_t, SAX>::value,
+                  "Missing/invalid function: bool boolean(bool)");
+    static_assert(is_detected_exact<bool, boolean_function_t, SAX>::value,
+                  "Missing/invalid function: bool boolean(bool)");
+    static_assert(
+        is_detected_exact<bool, number_integer_function_t, SAX,
+        number_integer_t>::value,
+        "Missing/invalid function: bool number_integer(number_integer_t)");
+    static_assert(
+        is_detected_exact<bool, number_unsigned_function_t, SAX,
+        number_unsigned_t>::value,
+        "Missing/invalid function: bool number_unsigned(number_unsigned_t)");
+    static_assert(is_detected_exact<bool, number_float_function_t, SAX,
+                  number_float_t, string_t>::value,
+                  "Missing/invalid function: bool number_float(number_float_t, const string_t&)");
+    static_assert(
+        is_detected_exact<bool, string_function_t, SAX, string_t>::value,
+        "Missing/invalid function: bool string(string_t&)");
+    static_assert(
+        is_detected_exact<bool, binary_function_t, SAX, binary_t>::value,
+        "Missing/invalid function: bool binary(binary_t&)");
+    static_assert(is_detected_exact<bool, start_object_function_t, SAX>::value,
+                  "Missing/invalid function: bool start_object(std::size_t)");
+    static_assert(is_detected_exact<bool, key_function_t, SAX, string_t>::value,
+                  "Missing/invalid function: bool key(string_t&)");
+    static_assert(is_detected_exact<bool, end_object_function_t, SAX>::value,
+                  "Missing/invalid function: bool end_object()");
+    static_assert(is_detected_exact<bool, start_array_function_t, SAX>::value,
+                  "Missing/invalid function: bool start_array(std::size_t)");
+    static_assert(is_detected_exact<bool, end_array_function_t, SAX>::value,
+                  "Missing/invalid function: bool end_array()");
+    static_assert(
+        is_detected_exact<bool, parse_error_function_t, SAX, exception_t>::value,
+        "Missing/invalid function: bool parse_error(std::size_t, const "
+        "std::string&, const exception&)");
+};
+}  // namespace detail
+}  // namespace nlohmann
+
+// #include <nlohmann/detail/meta/type_traits.hpp>
+
+// #include <nlohmann/detail/value_t.hpp>
+
+
+namespace nlohmann
+{
+namespace detail
+{
+
+/// how to treat CBOR tags
+enum class cbor_tag_handler_t
+{
+    error,   ///< throw a parse_error exception in case of a tag
+    ignore,  ///< ignore tags
+    store    ///< store tags as binary type
+};
+
+/*!
+@brief determine system byte order
+
+@return true if and only if system's byte order is little endian
+
+@note from https://stackoverflow.com/a/1001328/266378
+*/
+static inline bool little_endianess(int num = 1) noexcept
+{
+    return *reinterpret_cast<char*>(&num) == 1;
+}
+
+
+///////////////////
+// binary reader //
+///////////////////
+
+/*!
+@brief deserialization of CBOR, MessagePack, and UBJSON values
+*/
+template<typename BasicJsonType, typename InputAdapterType, typename SAX = json_sax_dom_parser<BasicJsonType>>
+class binary_reader
+{
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using string_t = typename BasicJsonType::string_t;
+    using binary_t = typename BasicJsonType::binary_t;
+    using json_sax_t = SAX;
+    using char_type = typename InputAdapterType::char_type;
+    using char_int_type = typename std::char_traits<char_type>::int_type;
+
+  public:
+    /*!
+    @brief create a binary reader
+
+    @param[in] adapter  input adapter to read from
+    */
+    explicit binary_reader(InputAdapterType&& adapter) noexcept : ia(std::move(adapter))
+    {
+        (void)detail::is_sax_static_asserts<SAX, BasicJsonType> {};
+    }
+
+    // make class move-only
+    binary_reader(const binary_reader&) = delete;
+    binary_reader(binary_reader&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
+    binary_reader& operator=(const binary_reader&) = delete;
+    binary_reader& operator=(binary_reader&&) = default; // NOLINT(hicpp-noexcept-move,performance-noexcept-move-constructor)
+    ~binary_reader() = default;
+
+    /*!
+    @param[in] format  the binary format to parse
+    @param[in] sax_    a SAX event processor
+    @param[in] strict  whether to expect the input to be consumed completed
+    @param[in] tag_handler  how to treat CBOR tags
+
+    @return whether parsing was successful
+    */
+    JSON_HEDLEY_NON_NULL(3)
+    bool sax_parse(const input_format_t format,
+                   json_sax_t* sax_,
+                   const bool strict = true,
+                   const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
+    {
+        sax = sax_;
+        bool result = false;
+
+        switch (format)
+        {
+            case input_format_t::bson:
+                result = parse_bson_internal();
+                break;
+
+            case input_format_t::cbor:
+                result = parse_cbor_internal(true, tag_handler);
+                break;
+
+            case input_format_t::msgpack:
+                result = parse_msgpack_internal();
+                break;
+
+            case input_format_t::ubjson:
+                result = parse_ubjson_internal();
+                break;
+
+            case input_format_t::json: // LCOV_EXCL_LINE
+            default:            // LCOV_EXCL_LINE
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+        }
+
+        // strict mode: next byte must be EOF
+        if (result && strict)
+        {
+            if (format == input_format_t::ubjson)
+            {
+                get_ignore_noop();
+            }
+            else
+            {
+                get();
+            }
+
+            if (JSON_HEDLEY_UNLIKELY(current != std::char_traits<char_type>::eof()))
+            {
+                return sax->parse_error(chars_read, get_token_string(),
+                                        parse_error::create(110, chars_read, exception_message(format, "expected end of input; last byte: 0x" + get_token_string(), "value"), BasicJsonType()));
+            }
+        }
+
+        return result;
+    }
+
+  private:
+    //////////
+    // BSON //
+    //////////
+
+    /*!
+    @brief Reads in a BSON-object and passes it to the SAX-parser.
+    @return whether a valid BSON-value was passed to the SAX parser
+    */
+    bool parse_bson_internal()
+    {
+        std::int32_t document_size{};
+        get_number<std::int32_t, true>(input_format_t::bson, document_size);
+
+        if (JSON_HEDLEY_UNLIKELY(!sax->start_object(std::size_t(-1))))
+        {
+            return false;
+        }
+
+        if (JSON_HEDLEY_UNLIKELY(!parse_bson_element_list(/*is_array*/false)))
+        {
+            return false;
+        }
+
+        return sax->end_object();
+    }
+
+    /*!
+    @brief Parses a C-style string from the BSON input.
+    @param[in,out] result  A reference to the string variable where the read
+                            string is to be stored.
+    @return `true` if the \x00-byte indicating the end of the string was
+             encountered before the EOF; false` indicates an unexpected EOF.
+    */
+    bool get_bson_cstr(string_t& result)
+    {
+        auto out = std::back_inserter(result);
+        while (true)
+        {
+            get();
+            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::bson, "cstring")))
+            {
+                return false;
+            }
+            if (current == 0x00)
+            {
+                return true;
+            }
+            *out++ = static_cast<typename string_t::value_type>(current);
+        }
+    }
+
+    /*!
+    @brief Parses a zero-terminated string of length @a len from the BSON
+           input.
+    @param[in] len  The length (including the zero-byte at the end) of the
+                    string to be read.
+    @param[in,out] result  A reference to the string variable where the read
+                            string is to be stored.
+    @tparam NumberType The type of the length @a len
+    @pre len >= 1
+    @return `true` if the string was successfully parsed
+    */
+    template<typename NumberType>
+    bool get_bson_string(const NumberType len, string_t& result)
+    {
+        if (JSON_HEDLEY_UNLIKELY(len < 1))
+        {
+            auto last_token = get_token_string();
+            return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::bson, "string length must be at least 1, is " + std::to_string(len), "string"), BasicJsonType()));
+        }
+
+        return get_string(input_format_t::bson, len - static_cast<NumberType>(1), result) && get() != std::char_traits<char_type>::eof();
+    }
+
+    /*!
+    @brief Parses a byte array input of length @a len from the BSON input.
+    @param[in] len  The length of the byte array to be read.
+    @param[in,out] result  A reference to the binary variable where the read
+                            array is to be stored.
+    @tparam NumberType The type of the length @a len
+    @pre len >= 0
+    @return `true` if the byte array was successfully parsed
+    */
+    template<typename NumberType>
+    bool get_bson_binary(const NumberType len, binary_t& result)
+    {
+        if (JSON_HEDLEY_UNLIKELY(len < 0))
+        {
+            auto last_token = get_token_string();
+            return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::bson, "byte array length cannot be negative, is " + std::to_string(len), "binary"), BasicJsonType()));
+        }
+
+        // All BSON binary values have a subtype
+        std::uint8_t subtype{};
+        get_number<std::uint8_t>(input_format_t::bson, subtype);
+        result.set_subtype(subtype);
+
+        return get_binary(input_format_t::bson, len, result);
+    }
+
+    /*!
+    @brief Read a BSON document element of the given @a element_type.
+    @param[in] element_type The BSON element type, c.f. http://bsonspec.org/spec.html
+    @param[in] element_type_parse_position The position in the input stream,
+               where the `element_type` was read.
+    @warning Not all BSON element types are supported yet. An unsupported
+             @a element_type will give rise to a parse_error.114:
+             Unsupported BSON record type 0x...
+    @return whether a valid BSON-object/array was passed to the SAX parser
+    */
+    bool parse_bson_element_internal(const char_int_type element_type,
+                                     const std::size_t element_type_parse_position)
+    {
+        switch (element_type)
+        {
+            case 0x01: // double
+            {
+                double number{};
+                return get_number<double, true>(input_format_t::bson, number) && sax->number_float(static_cast<number_float_t>(number), "");
+            }
+
+            case 0x02: // string
+            {
+                std::int32_t len{};
+                string_t value;
+                return get_number<std::int32_t, true>(input_format_t::bson, len) && get_bson_string(len, value) && sax->string(value);
+            }
+
+            case 0x03: // object
+            {
+                return parse_bson_internal();
+            }
+
+            case 0x04: // array
+            {
+                return parse_bson_array();
+            }
+
+            case 0x05: // binary
+            {
+                std::int32_t len{};
+                binary_t value;
+                return get_number<std::int32_t, true>(input_format_t::bson, len) && get_bson_binary(len, value) && sax->binary(value);
+            }
+
+            case 0x08: // boolean
+            {
+                return sax->boolean(get() != 0);
+            }
+
+            case 0x0A: // null
+            {
+                return sax->null();
+            }
+
+            case 0x10: // int32
+            {
+                std::int32_t value{};
+                return get_number<std::int32_t, true>(input_format_t::bson, value) && sax->number_integer(value);
+            }
+
+            case 0x12: // int64
+            {
+                std::int64_t value{};
+                return get_number<std::int64_t, true>(input_format_t::bson, value) && sax->number_integer(value);
+            }
+
+            default: // anything else not supported (yet)
+            {
+                std::array<char, 3> cr{{}};
+                (std::snprintf)(cr.data(), cr.size(), "%.2hhX", static_cast<unsigned char>(element_type)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                return sax->parse_error(element_type_parse_position, std::string(cr.data()), parse_error::create(114, element_type_parse_position, "Unsupported BSON record type 0x" + std::string(cr.data()), BasicJsonType()));
+            }
+        }
+    }
+
+    /*!
+    @brief Read a BSON element list (as specified in the BSON-spec)
+
+    The same binary layout is used for objects and arrays, hence it must be
+    indicated with the argument @a is_array which one is expected
+    (true --> array, false --> object).
+
+    @param[in] is_array Determines if the element list being read is to be
+                        treated as an object (@a is_array == false), or as an
+                        array (@a is_array == true).
+    @return whether a valid BSON-object/array was passed to the SAX parser
+    */
+    bool parse_bson_element_list(const bool is_array)
+    {
+        string_t key;
+
+        while (auto element_type = get())
+        {
+            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::bson, "element list")))
+            {
+                return false;
+            }
+
+            const std::size_t element_type_parse_position = chars_read;
+            if (JSON_HEDLEY_UNLIKELY(!get_bson_cstr(key)))
+            {
+                return false;
+            }
+
+            if (!is_array && !sax->key(key))
+            {
+                return false;
+            }
+
+            if (JSON_HEDLEY_UNLIKELY(!parse_bson_element_internal(element_type, element_type_parse_position)))
+            {
+                return false;
+            }
+
+            // get_bson_cstr only appends
+            key.clear();
+        }
+
+        return true;
+    }
+
+    /*!
+    @brief Reads an array from the BSON input and passes it to the SAX-parser.
+    @return whether a valid BSON-array was passed to the SAX parser
+    */
+    bool parse_bson_array()
+    {
+        std::int32_t document_size{};
+        get_number<std::int32_t, true>(input_format_t::bson, document_size);
+
+        if (JSON_HEDLEY_UNLIKELY(!sax->start_array(std::size_t(-1))))
+        {
+            return false;
+        }
+
+        if (JSON_HEDLEY_UNLIKELY(!parse_bson_element_list(/*is_array*/true)))
+        {
+            return false;
+        }
+
+        return sax->end_array();
+    }
+
+    //////////
+    // CBOR //
+    //////////
+
+    /*!
+    @param[in] get_char  whether a new character should be retrieved from the
+                         input (true) or whether the last read character should
+                         be considered instead (false)
+    @param[in] tag_handler how CBOR tags should be treated
+
+    @return whether a valid CBOR value was passed to the SAX parser
+    */
+    bool parse_cbor_internal(const bool get_char,
+                             const cbor_tag_handler_t tag_handler)
+    {
+        switch (get_char ? get() : current)
+        {
+            // EOF
+            case std::char_traits<char_type>::eof():
+                return unexpect_eof(input_format_t::cbor, "value");
+
+            // Integer 0x00..0x17 (0..23)
+            case 0x00:
+            case 0x01:
+            case 0x02:
+            case 0x03:
+            case 0x04:
+            case 0x05:
+            case 0x06:
+            case 0x07:
+            case 0x08:
+            case 0x09:
+            case 0x0A:
+            case 0x0B:
+            case 0x0C:
+            case 0x0D:
+            case 0x0E:
+            case 0x0F:
+            case 0x10:
+            case 0x11:
+            case 0x12:
+            case 0x13:
+            case 0x14:
+            case 0x15:
+            case 0x16:
+            case 0x17:
+                return sax->number_unsigned(static_cast<number_unsigned_t>(current));
+
+            case 0x18: // Unsigned integer (one-byte uint8_t follows)
+            {
+                std::uint8_t number{};
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
+            }
+
+            case 0x19: // Unsigned integer (two-byte uint16_t follows)
+            {
+                std::uint16_t number{};
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
+            }
+
+            case 0x1A: // Unsigned integer (four-byte uint32_t follows)
+            {
+                std::uint32_t number{};
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
+            }
+
+            case 0x1B: // Unsigned integer (eight-byte uint64_t follows)
+            {
+                std::uint64_t number{};
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
+            }
+
+            // Negative integer -1-0x00..-1-0x17 (-1..-24)
+            case 0x20:
+            case 0x21:
+            case 0x22:
+            case 0x23:
+            case 0x24:
+            case 0x25:
+            case 0x26:
+            case 0x27:
+            case 0x28:
+            case 0x29:
+            case 0x2A:
+            case 0x2B:
+            case 0x2C:
+            case 0x2D:
+            case 0x2E:
+            case 0x2F:
+            case 0x30:
+            case 0x31:
+            case 0x32:
+            case 0x33:
+            case 0x34:
+            case 0x35:
+            case 0x36:
+            case 0x37:
+                return sax->number_integer(static_cast<std::int8_t>(0x20 - 1 - current));
+
+            case 0x38: // Negative integer (one-byte uint8_t follows)
+            {
+                std::uint8_t number{};
+                return get_number(input_format_t::cbor, number) && sax->number_integer(static_cast<number_integer_t>(-1) - number);
+            }
+
+            case 0x39: // Negative integer -1-n (two-byte uint16_t follows)
+            {
+                std::uint16_t number{};
+                return get_number(input_format_t::cbor, number) && sax->number_integer(static_cast<number_integer_t>(-1) - number);
+            }
+
+            case 0x3A: // Negative integer -1-n (four-byte uint32_t follows)
+            {
+                std::uint32_t number{};
+                return get_number(input_format_t::cbor, number) && sax->number_integer(static_cast<number_integer_t>(-1) - number);
+            }
+
+            case 0x3B: // Negative integer -1-n (eight-byte uint64_t follows)
+            {
+                std::uint64_t number{};
+                return get_number(input_format_t::cbor, number) && sax->number_integer(static_cast<number_integer_t>(-1)
+                        - static_cast<number_integer_t>(number));
+            }
+
+            // Binary data (0x00..0x17 bytes follow)
+            case 0x40:
+            case 0x41:
+            case 0x42:
+            case 0x43:
+            case 0x44:
+            case 0x45:
+            case 0x46:
+            case 0x47:
+            case 0x48:
+            case 0x49:
+            case 0x4A:
+            case 0x4B:
+            case 0x4C:
+            case 0x4D:
+            case 0x4E:
+            case 0x4F:
+            case 0x50:
+            case 0x51:
+            case 0x52:
+            case 0x53:
+            case 0x54:
+            case 0x55:
+            case 0x56:
+            case 0x57:
+            case 0x58: // Binary data (one-byte uint8_t for n follows)
+            case 0x59: // Binary data (two-byte uint16_t for n follow)
+            case 0x5A: // Binary data (four-byte uint32_t for n follow)
+            case 0x5B: // Binary data (eight-byte uint64_t for n follow)
+            case 0x5F: // Binary data (indefinite length)
+            {
+                binary_t b;
+                return get_cbor_binary(b) && sax->binary(b);
+            }
+
+            // UTF-8 string (0x00..0x17 bytes follow)
+            case 0x60:
+            case 0x61:
+            case 0x62:
+            case 0x63:
+            case 0x64:
+            case 0x65:
+            case 0x66:
+            case 0x67:
+            case 0x68:
+            case 0x69:
+            case 0x6A:
+            case 0x6B:
+            case 0x6C:
+            case 0x6D:
+            case 0x6E:
+            case 0x6F:
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77:
+            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
+            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
+            case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
+            case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
+            case 0x7F: // UTF-8 string (indefinite length)
+            {
+                string_t s;
+                return get_cbor_string(s) && sax->string(s);
+            }
+
+            // array (0x00..0x17 data items follow)
+            case 0x80:
+            case 0x81:
+            case 0x82:
+            case 0x83:
+            case 0x84:
+            case 0x85:
+            case 0x86:
+            case 0x87:
+            case 0x88:
+            case 0x89:
+            case 0x8A:
+            case 0x8B:
+            case 0x8C:
+            case 0x8D:
+            case 0x8E:
+            case 0x8F:
+            case 0x90:
+            case 0x91:
+            case 0x92:
+            case 0x93:
+            case 0x94:
+            case 0x95:
+            case 0x96:
+            case 0x97:
+                return get_cbor_array(static_cast<std::size_t>(static_cast<unsigned int>(current) & 0x1Fu), tag_handler);
+
+            case 0x98: // array (one-byte uint8_t for n follows)
+            {
+                std::uint8_t len{};
+                return get_number(input_format_t::cbor, len) && get_cbor_array(static_cast<std::size_t>(len), tag_handler);
+            }
+
+            case 0x99: // array (two-byte uint16_t for n follow)
+            {
+                std::uint16_t len{};
+                return get_number(input_format_t::cbor, len) && get_cbor_array(static_cast<std::size_t>(len), tag_handler);
+            }
+
+            case 0x9A: // array (four-byte uint32_t for n follow)
+            {
+                std::uint32_t len{};
+                return get_number(input_format_t::cbor, len) && get_cbor_array(static_cast<std::size_t>(len), tag_handler);
+            }
+
+            case 0x9B: // array (eight-byte uint64_t for n follow)
+            {
+                std::uint64_t len{};
+                return get_number(input_format_t::cbor, len) && get_cbor_array(detail::conditional_static_cast<std::size_t>(len), tag_handler);
+            }
+
+            case 0x9F: // array (indefinite length)
+                return get_cbor_array(std::size_t(-1), tag_handler);
+
+            // map (0x00..0x17 pairs of data items follow)
+            case 0xA0:
+            case 0xA1:
+            case 0xA2:
+            case 0xA3:
+            case 0xA4:
+            case 0xA5:
+            case 0xA6:
+            case 0xA7:
+            case 0xA8:
+            case 0xA9:
+            case 0xAA:
+            case 0xAB:
+            case 0xAC:
+            case 0xAD:
+            case 0xAE:
+            case 0xAF:
+            case 0xB0:
+            case 0xB1:
+            case 0xB2:
+            case 0xB3:
+            case 0xB4:
+            case 0xB5:
+            case 0xB6:
+            case 0xB7:
+                return get_cbor_object(static_cast<std::size_t>(static_cast<unsigned int>(current) & 0x1Fu), tag_handler);
+
+            case 0xB8: // map (one-byte uint8_t for n follows)
+            {
+                std::uint8_t len{};
+                return get_number(input_format_t::cbor, len) && get_cbor_object(static_cast<std::size_t>(len), tag_handler);
+            }
+
+            case 0xB9: // map (two-byte uint16_t for n follow)
+            {
+                std::uint16_t len{};
+                return get_number(input_format_t::cbor, len) && get_cbor_object(static_cast<std::size_t>(len), tag_handler);
+            }
+
+            case 0xBA: // map (four-byte uint32_t for n follow)
+            {
+                std::uint32_t len{};
+                return get_number(input_format_t::cbor, len) && get_cbor_object(static_cast<std::size_t>(len), tag_handler);
+            }
+
+            case 0xBB: // map (eight-byte uint64_t for n follow)
+            {
+                std::uint64_t len{};
+                return get_number(input_format_t::cbor, len) && get_cbor_object(detail::conditional_static_cast<std::size_t>(len), tag_handler);
+            }
+
+            case 0xBF: // map (indefinite length)
+                return get_cbor_object(std::size_t(-1), tag_handler);
+
+            case 0xC6: // tagged item
+            case 0xC7:
+            case 0xC8:
+            case 0xC9:
+            case 0xCA:
+            case 0xCB:
+            case 0xCC:
+            case 0xCD:
+            case 0xCE:
+            case 0xCF:
+            case 0xD0:
+            case 0xD1:
+            case 0xD2:
+            case 0xD3:
+            case 0xD4:
+            case 0xD8: // tagged item (1 bytes follow)
+            case 0xD9: // tagged item (2 bytes follow)
+            case 0xDA: // tagged item (4 bytes follow)
+            case 0xDB: // tagged item (8 bytes follow)
+            {
+                switch (tag_handler)
+                {
+                    case cbor_tag_handler_t::error:
+                    {
+                        auto last_token = get_token_string();
+                        return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::cbor, "invalid byte: 0x" + last_token, "value"), BasicJsonType()));
+                    }
+
+                    case cbor_tag_handler_t::ignore:
+                    {
+                        // ignore binary subtype
+                        switch (current)
+                        {
+                            case 0xD8:
+                            {
+                                std::uint8_t subtype_to_ignore{};
+                                get_number(input_format_t::cbor, subtype_to_ignore);
+                                break;
+                            }
+                            case 0xD9:
+                            {
+                                std::uint16_t subtype_to_ignore{};
+                                get_number(input_format_t::cbor, subtype_to_ignore);
+                                break;
+                            }
+                            case 0xDA:
+                            {
+                                std::uint32_t subtype_to_ignore{};
+                                get_number(input_format_t::cbor, subtype_to_ignore);
+                                break;
+                            }
+                            case 0xDB:
+                            {
+                                std::uint64_t subtype_to_ignore{};
+                                get_number(input_format_t::cbor, subtype_to_ignore);
+                                break;
+                            }
+                            default:
+                                break;
+                        }
+                        return parse_cbor_internal(true, tag_handler);
+                    }
+
+                    case cbor_tag_handler_t::store:
+                    {
+                        binary_t b;
+                        // use binary subtype and store in binary container
+                        switch (current)
+                        {
+                            case 0xD8:
+                            {
+                                std::uint8_t subtype{};
+                                get_number(input_format_t::cbor, subtype);
+                                b.set_subtype(detail::conditional_static_cast<typename binary_t::subtype_type>(subtype));
+                                break;
+                            }
+                            case 0xD9:
+                            {
+                                std::uint16_t subtype{};
+                                get_number(input_format_t::cbor, subtype);
+                                b.set_subtype(detail::conditional_static_cast<typename binary_t::subtype_type>(subtype));
+                                break;
+                            }
+                            case 0xDA:
+                            {
+                                std::uint32_t subtype{};
+                                get_number(input_format_t::cbor, subtype);
+                                b.set_subtype(detail::conditional_static_cast<typename binary_t::subtype_type>(subtype));
+                                break;
+                            }
+                            case 0xDB:
+                            {
+                                std::uint64_t subtype{};
+                                get_number(input_format_t::cbor, subtype);
+                                b.set_subtype(detail::conditional_static_cast<typename binary_t::subtype_type>(subtype));
+                                break;
+                            }
+                            default:
+                                return parse_cbor_internal(true, tag_handler);
+                        }
+                        get();
+                        return get_cbor_binary(b) && sax->binary(b);
+                    }
+
+                    default:                 // LCOV_EXCL_LINE
+                        JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+                        return false;        // LCOV_EXCL_LINE
+                }
+            }
+
+            case 0xF4: // false
+                return sax->boolean(false);
+
+            case 0xF5: // true
+                return sax->boolean(true);
+
+            case 0xF6: // null
+                return sax->null();
+
+            case 0xF9: // Half-Precision Float (two-byte IEEE 754)
+            {
+                const auto byte1_raw = get();
+                if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "number")))
+                {
+                    return false;
+                }
+                const auto byte2_raw = get();
+                if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "number")))
+                {
+                    return false;
+                }
+
+                const auto byte1 = static_cast<unsigned char>(byte1_raw);
+                const auto byte2 = static_cast<unsigned char>(byte2_raw);
+
+                // code from RFC 7049, Appendix D, Figure 3:
+                // As half-precision floating-point numbers were only added
+                // to IEEE 754 in 2008, today's programming platforms often
+                // still only have limited support for them. It is very
+                // easy to include at least decoding support for them even
+                // without such support. An example of a small decoder for
+                // half-precision floating-point numbers in the C language
+                // is shown in Fig. 3.
+                const auto half = static_cast<unsigned int>((byte1 << 8u) + byte2);
+                const double val = [&half]
+                {
+                    const int exp = (half >> 10u) & 0x1Fu;
+                    const unsigned int mant = half & 0x3FFu;
+                    JSON_ASSERT(0 <= exp&& exp <= 32);
+                    JSON_ASSERT(mant <= 1024);
+                    switch (exp)
+                    {
+                        case 0:
+                            return std::ldexp(mant, -24);
+                        case 31:
+                            return (mant == 0)
+                            ? std::numeric_limits<double>::infinity()
+                            : std::numeric_limits<double>::quiet_NaN();
+                        default:
+                            return std::ldexp(mant + 1024, exp - 25);
+                    }
+                }();
+                return sax->number_float((half & 0x8000u) != 0
+                                         ? static_cast<number_float_t>(-val)
+                                         : static_cast<number_float_t>(val), "");
+            }
+
+            case 0xFA: // Single-Precision Float (four-byte IEEE 754)
+            {
+                float number{};
+                return get_number(input_format_t::cbor, number) && sax->number_float(static_cast<number_float_t>(number), "");
+            }
+
+            case 0xFB: // Double-Precision Float (eight-byte IEEE 754)
+            {
+                double number{};
+                return get_number(input_format_t::cbor, number) && sax->number_float(static_cast<number_float_t>(number), "");
+            }
+
+            default: // anything else (0xFF is handled inside the other types)
+            {
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::cbor, "invalid byte: 0x" + last_token, "value"), BasicJsonType()));
+            }
+        }
+    }
+
+    /*!
+    @brief reads a CBOR string
+
+    This function first reads starting bytes to determine the expected
+    string length and then copies this number of bytes into a string.
+    Additionally, CBOR's strings with indefinite lengths are supported.
+
+    @param[out] result  created string
+
+    @return whether string creation completed
+    */
+    bool get_cbor_string(string_t& result)
+    {
+        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "string")))
+        {
+            return false;
+        }
+
+        switch (current)
+        {
+            // UTF-8 string (0x00..0x17 bytes follow)
+            case 0x60:
+            case 0x61:
+            case 0x62:
+            case 0x63:
+            case 0x64:
+            case 0x65:
+            case 0x66:
+            case 0x67:
+            case 0x68:
+            case 0x69:
+            case 0x6A:
+            case 0x6B:
+            case 0x6C:
+            case 0x6D:
+            case 0x6E:
+            case 0x6F:
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77:
+            {
+                return get_string(input_format_t::cbor, static_cast<unsigned int>(current) & 0x1Fu, result);
+            }
+
+            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
+            {
+                std::uint8_t len{};
+                return get_number(input_format_t::cbor, len) && get_string(input_format_t::cbor, len, result);
+            }
+
+            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
+            {
+                std::uint16_t len{};
+                return get_number(input_format_t::cbor, len) && get_string(input_format_t::cbor, len, result);
+            }
+
+            case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
+            {
+                std::uint32_t len{};
+                return get_number(input_format_t::cbor, len) && get_string(input_format_t::cbor, len, result);
+            }
+
+            case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
+            {
+                std::uint64_t len{};
+                return get_number(input_format_t::cbor, len) && get_string(input_format_t::cbor, len, result);
+            }
+
+            case 0x7F: // UTF-8 string (indefinite length)
+            {
+                while (get() != 0xFF)
+                {
+                    string_t chunk;
+                    if (!get_cbor_string(chunk))
+                    {
+                        return false;
+                    }
+                    result.append(chunk);
+                }
+                return true;
+            }
+
+            default:
+            {
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::cbor, "expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0x" + last_token, "string"), BasicJsonType()));
+            }
+        }
+    }
+
+    /*!
+    @brief reads a CBOR byte array
+
+    This function first reads starting bytes to determine the expected
+    byte array length and then copies this number of bytes into the byte array.
+    Additionally, CBOR's byte arrays with indefinite lengths are supported.
+
+    @param[out] result  created byte array
+
+    @return whether byte array creation completed
+    */
+    bool get_cbor_binary(binary_t& result)
+    {
+        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "binary")))
+        {
+            return false;
+        }
+
+        switch (current)
+        {
+            // Binary data (0x00..0x17 bytes follow)
+            case 0x40:
+            case 0x41:
+            case 0x42:
+            case 0x43:
+            case 0x44:
+            case 0x45:
+            case 0x46:
+            case 0x47:
+            case 0x48:
+            case 0x49:
+            case 0x4A:
+            case 0x4B:
+            case 0x4C:
+            case 0x4D:
+            case 0x4E:
+            case 0x4F:
+            case 0x50:
+            case 0x51:
+            case 0x52:
+            case 0x53:
+            case 0x54:
+            case 0x55:
+            case 0x56:
+            case 0x57:
+            {
+                return get_binary(input_format_t::cbor, static_cast<unsigned int>(current) & 0x1Fu, result);
+            }
+
+            case 0x58: // Binary data (one-byte uint8_t for n follows)
+            {
+                std::uint8_t len{};
+                return get_number(input_format_t::cbor, len) &&
+                       get_binary(input_format_t::cbor, len, result);
+            }
+
+            case 0x59: // Binary data (two-byte uint16_t for n follow)
+            {
+                std::uint16_t len{};
+                return get_number(input_format_t::cbor, len) &&
+                       get_binary(input_format_t::cbor, len, result);
+            }
+
+            case 0x5A: // Binary data (four-byte uint32_t for n follow)
+            {
+                std::uint32_t len{};
+                return get_number(input_format_t::cbor, len) &&
+                       get_binary(input_format_t::cbor, len, result);
+            }
+
+            case 0x5B: // Binary data (eight-byte uint64_t for n follow)
+            {
+                std::uint64_t len{};
+                return get_number(input_format_t::cbor, len) &&
+                       get_binary(input_format_t::cbor, len, result);
+            }
+
+            case 0x5F: // Binary data (indefinite length)
+            {
+                while (get() != 0xFF)
+                {
+                    binary_t chunk;
+                    if (!get_cbor_binary(chunk))
+                    {
+                        return false;
+                    }
+                    result.insert(result.end(), chunk.begin(), chunk.end());
+                }
+                return true;
+            }
+
+            default:
+            {
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::cbor, "expected length specification (0x40-0x5B) or indefinite binary array type (0x5F); last byte: 0x" + last_token, "binary"), BasicJsonType()));
+            }
+        }
+    }
+
+    /*!
+    @param[in] len  the length of the array or std::size_t(-1) for an
+                    array of indefinite size
+    @param[in] tag_handler how CBOR tags should be treated
+    @return whether array creation completed
+    */
+    bool get_cbor_array(const std::size_t len,
+                        const cbor_tag_handler_t tag_handler)
+    {
+        if (JSON_HEDLEY_UNLIKELY(!sax->start_array(len)))
+        {
+            return false;
+        }
+
+        if (len != std::size_t(-1))
+        {
+            for (std::size_t i = 0; i < len; ++i)
+            {
+                if (JSON_HEDLEY_UNLIKELY(!parse_cbor_internal(true, tag_handler)))
+                {
+                    return false;
+                }
+            }
+        }
+        else
+        {
+            while (get() != 0xFF)
+            {
+                if (JSON_HEDLEY_UNLIKELY(!parse_cbor_internal(false, tag_handler)))
+                {
+                    return false;
+                }
+            }
+        }
+
+        return sax->end_array();
+    }
+
+    /*!
+    @param[in] len  the length of the object or std::size_t(-1) for an
+                    object of indefinite size
+    @param[in] tag_handler how CBOR tags should be treated
+    @return whether object creation completed
+    */
+    bool get_cbor_object(const std::size_t len,
+                         const cbor_tag_handler_t tag_handler)
+    {
+        if (JSON_HEDLEY_UNLIKELY(!sax->start_object(len)))
+        {
+            return false;
+        }
+
+        if (len != 0)
+        {
+            string_t key;
+            if (len != std::size_t(-1))
+            {
+                for (std::size_t i = 0; i < len; ++i)
+                {
+                    get();
+                    if (JSON_HEDLEY_UNLIKELY(!get_cbor_string(key) || !sax->key(key)))
+                    {
+                        return false;
+                    }
+
+                    if (JSON_HEDLEY_UNLIKELY(!parse_cbor_internal(true, tag_handler)))
+                    {
+                        return false;
+                    }
+                    key.clear();
+                }
+            }
+            else
+            {
+                while (get() != 0xFF)
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!get_cbor_string(key) || !sax->key(key)))
+                    {
+                        return false;
+                    }
+
+                    if (JSON_HEDLEY_UNLIKELY(!parse_cbor_internal(true, tag_handler)))
+                    {
+                        return false;
+                    }
+                    key.clear();
+                }
+            }
+        }
+
+        return sax->end_object();
+    }
+
+    /////////////
+    // MsgPack //
+    /////////////
+
+    /*!
+    @return whether a valid MessagePack value was passed to the SAX parser
+    */
+    bool parse_msgpack_internal()
+    {
+        switch (get())
+        {
+            // EOF
+            case std::char_traits<char_type>::eof():
+                return unexpect_eof(input_format_t::msgpack, "value");
+
+            // positive fixint
+            case 0x00:
+            case 0x01:
+            case 0x02:
+            case 0x03:
+            case 0x04:
+            case 0x05:
+            case 0x06:
+            case 0x07:
+            case 0x08:
+            case 0x09:
+            case 0x0A:
+            case 0x0B:
+            case 0x0C:
+            case 0x0D:
+            case 0x0E:
+            case 0x0F:
+            case 0x10:
+            case 0x11:
+            case 0x12:
+            case 0x13:
+            case 0x14:
+            case 0x15:
+            case 0x16:
+            case 0x17:
+            case 0x18:
+            case 0x19:
+            case 0x1A:
+            case 0x1B:
+            case 0x1C:
+            case 0x1D:
+            case 0x1E:
+            case 0x1F:
+            case 0x20:
+            case 0x21:
+            case 0x22:
+            case 0x23:
+            case 0x24:
+            case 0x25:
+            case 0x26:
+            case 0x27:
+            case 0x28:
+            case 0x29:
+            case 0x2A:
+            case 0x2B:
+            case 0x2C:
+            case 0x2D:
+            case 0x2E:
+            case 0x2F:
+            case 0x30:
+            case 0x31:
+            case 0x32:
+            case 0x33:
+            case 0x34:
+            case 0x35:
+            case 0x36:
+            case 0x37:
+            case 0x38:
+            case 0x39:
+            case 0x3A:
+            case 0x3B:
+            case 0x3C:
+            case 0x3D:
+            case 0x3E:
+            case 0x3F:
+            case 0x40:
+            case 0x41:
+            case 0x42:
+            case 0x43:
+            case 0x44:
+            case 0x45:
+            case 0x46:
+            case 0x47:
+            case 0x48:
+            case 0x49:
+            case 0x4A:
+            case 0x4B:
+            case 0x4C:
+            case 0x4D:
+            case 0x4E:
+            case 0x4F:
+            case 0x50:
+            case 0x51:
+            case 0x52:
+            case 0x53:
+            case 0x54:
+            case 0x55:
+            case 0x56:
+            case 0x57:
+            case 0x58:
+            case 0x59:
+            case 0x5A:
+            case 0x5B:
+            case 0x5C:
+            case 0x5D:
+            case 0x5E:
+            case 0x5F:
+            case 0x60:
+            case 0x61:
+            case 0x62:
+            case 0x63:
+            case 0x64:
+            case 0x65:
+            case 0x66:
+            case 0x67:
+            case 0x68:
+            case 0x69:
+            case 0x6A:
+            case 0x6B:
+            case 0x6C:
+            case 0x6D:
+            case 0x6E:
+            case 0x6F:
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77:
+            case 0x78:
+            case 0x79:
+            case 0x7A:
+            case 0x7B:
+            case 0x7C:
+            case 0x7D:
+            case 0x7E:
+            case 0x7F:
+                return sax->number_unsigned(static_cast<number_unsigned_t>(current));
+
+            // fixmap
+            case 0x80:
+            case 0x81:
+            case 0x82:
+            case 0x83:
+            case 0x84:
+            case 0x85:
+            case 0x86:
+            case 0x87:
+            case 0x88:
+            case 0x89:
+            case 0x8A:
+            case 0x8B:
+            case 0x8C:
+            case 0x8D:
+            case 0x8E:
+            case 0x8F:
+                return get_msgpack_object(static_cast<std::size_t>(static_cast<unsigned int>(current) & 0x0Fu));
+
+            // fixarray
+            case 0x90:
+            case 0x91:
+            case 0x92:
+            case 0x93:
+            case 0x94:
+            case 0x95:
+            case 0x96:
+            case 0x97:
+            case 0x98:
+            case 0x99:
+            case 0x9A:
+            case 0x9B:
+            case 0x9C:
+            case 0x9D:
+            case 0x9E:
+            case 0x9F:
+                return get_msgpack_array(static_cast<std::size_t>(static_cast<unsigned int>(current) & 0x0Fu));
+
+            // fixstr
+            case 0xA0:
+            case 0xA1:
+            case 0xA2:
+            case 0xA3:
+            case 0xA4:
+            case 0xA5:
+            case 0xA6:
+            case 0xA7:
+            case 0xA8:
+            case 0xA9:
+            case 0xAA:
+            case 0xAB:
+            case 0xAC:
+            case 0xAD:
+            case 0xAE:
+            case 0xAF:
+            case 0xB0:
+            case 0xB1:
+            case 0xB2:
+            case 0xB3:
+            case 0xB4:
+            case 0xB5:
+            case 0xB6:
+            case 0xB7:
+            case 0xB8:
+            case 0xB9:
+            case 0xBA:
+            case 0xBB:
+            case 0xBC:
+            case 0xBD:
+            case 0xBE:
+            case 0xBF:
+            case 0xD9: // str 8
+            case 0xDA: // str 16
+            case 0xDB: // str 32
+            {
+                string_t s;
+                return get_msgpack_string(s) && sax->string(s);
+            }
 
-#include <ciso646> // not
-#include <iterator> // iterator, random_access_iterator_tag, bidirectional_iterator_tag, advance, next
-#include <type_traits> // conditional, is_const, remove_const
+            case 0xC0: // nil
+                return sax->null();
 
-// #include <nlohmann/detail/exceptions.hpp>
+            case 0xC2: // false
+                return sax->boolean(false);
 
-// #include <nlohmann/detail/iterators/internal_iterator.hpp>
+            case 0xC3: // true
+                return sax->boolean(true);
 
-// #include <nlohmann/detail/iterators/primitive_iterator.hpp>
+            case 0xC4: // bin 8
+            case 0xC5: // bin 16
+            case 0xC6: // bin 32
+            case 0xC7: // ext 8
+            case 0xC8: // ext 16
+            case 0xC9: // ext 32
+            case 0xD4: // fixext 1
+            case 0xD5: // fixext 2
+            case 0xD6: // fixext 4
+            case 0xD7: // fixext 8
+            case 0xD8: // fixext 16
+            {
+                binary_t b;
+                return get_msgpack_binary(b) && sax->binary(b);
+            }
 
-// #include <nlohmann/detail/macro_scope.hpp>
+            case 0xCA: // float 32
+            {
+                float number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_float(static_cast<number_float_t>(number), "");
+            }
 
-// #include <nlohmann/detail/meta/cpp_future.hpp>
+            case 0xCB: // float 64
+            {
+                double number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_float(static_cast<number_float_t>(number), "");
+            }
 
-// #include <nlohmann/detail/value_t.hpp>
+            case 0xCC: // uint 8
+            {
+                std::uint8_t number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
+            }
 
+            case 0xCD: // uint 16
+            {
+                std::uint16_t number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
+            }
 
-namespace nlohmann
-{
-namespace detail
-{
-// forward declare, to be able to friend it later on
-template<typename IteratorType> class iteration_proxy;
-template<typename IteratorType> class iteration_proxy_value;
+            case 0xCE: // uint 32
+            {
+                std::uint32_t number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
+            }
 
-/*!
-@brief a template for a bidirectional iterator for the @ref basic_json class
-This class implements a both iterators (iterator and const_iterator) for the
-@ref basic_json class.
-@note An iterator is called *initialized* when a pointer to a JSON value has
-      been set (e.g., by a constructor or a copy assignment). If the iterator is
-      default-constructed, it is *uninitialized* and most methods are undefined.
-      **The library uses assertions to detect calls on uninitialized iterators.**
-@requirement The class satisfies the following concept requirements:
--
-[BidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator):
-  The iterator that can be moved can be moved in both directions (i.e.
-  incremented and decremented).
-@since version 1.0.0, simplified in version 2.0.9, change to bidirectional
-       iterators in version 3.0.0 (see https://github.com/nlohmann/json/issues/593)
-*/
-template<typename BasicJsonType>
-class iter_impl
-{
-    /// allow basic_json to access private members
-    friend iter_impl<typename std::conditional<std::is_const<BasicJsonType>::value, typename std::remove_const<BasicJsonType>::type, const BasicJsonType>::type>;
-    friend BasicJsonType;
-    friend iteration_proxy<iter_impl>;
-    friend iteration_proxy_value<iter_impl>;
+            case 0xCF: // uint 64
+            {
+                std::uint64_t number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
+            }
 
-    using object_t = typename BasicJsonType::object_t;
-    using array_t = typename BasicJsonType::array_t;
-    // make sure BasicJsonType is basic_json or const basic_json
-    static_assert(is_basic_json<typename std::remove_const<BasicJsonType>::type>::value,
-                  "iter_impl only accepts (const) basic_json");
+            case 0xD0: // int 8
+            {
+                std::int8_t number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
+            }
 
-  public:
+            case 0xD1: // int 16
+            {
+                std::int16_t number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
+            }
 
-    /// The std::iterator class template (used as a base class to provide typedefs) is deprecated in C++17.
-    /// The C++ Standard has never required user-defined iterators to derive from std::iterator.
-    /// A user-defined iterator should provide publicly accessible typedefs named
-    /// iterator_category, value_type, difference_type, pointer, and reference.
-    /// Note that value_type is required to be non-const, even for constant iterators.
-    using iterator_category = std::bidirectional_iterator_tag;
+            case 0xD2: // int 32
+            {
+                std::int32_t number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
+            }
 
-    /// the type of the values when the iterator is dereferenced
-    using value_type = typename BasicJsonType::value_type;
-    /// a type to represent differences between iterators
-    using difference_type = typename BasicJsonType::difference_type;
-    /// defines a pointer to the type iterated over (value_type)
-    using pointer = typename std::conditional<std::is_const<BasicJsonType>::value,
-          typename BasicJsonType::const_pointer,
-          typename BasicJsonType::pointer>::type;
-    /// defines a reference to the type iterated over (value_type)
-    using reference =
-        typename std::conditional<std::is_const<BasicJsonType>::value,
-        typename BasicJsonType::const_reference,
-        typename BasicJsonType::reference>::type;
+            case 0xD3: // int 64
+            {
+                std::int64_t number{};
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
+            }
 
-    /// default constructor
-    iter_impl() = default;
+            case 0xDC: // array 16
+            {
+                std::uint16_t len{};
+                return get_number(input_format_t::msgpack, len) && get_msgpack_array(static_cast<std::size_t>(len));
+            }
 
-    /*!
-    @brief constructor for a given JSON instance
-    @param[in] object  pointer to a JSON object for this iterator
-    @pre object != nullptr
-    @post The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    explicit iter_impl(pointer object) noexcept : m_object(object)
-    {
-        assert(m_object != nullptr);
+            case 0xDD: // array 32
+            {
+                std::uint32_t len{};
+                return get_number(input_format_t::msgpack, len) && get_msgpack_array(static_cast<std::size_t>(len));
+            }
 
-        switch (m_object->m_type)
-        {
-            case value_t::object:
+            case 0xDE: // map 16
             {
-                m_it.object_iterator = typename object_t::iterator();
-                break;
+                std::uint16_t len{};
+                return get_number(input_format_t::msgpack, len) && get_msgpack_object(static_cast<std::size_t>(len));
             }
 
-            case value_t::array:
+            case 0xDF: // map 32
             {
-                m_it.array_iterator = typename array_t::iterator();
-                break;
+                std::uint32_t len{};
+                return get_number(input_format_t::msgpack, len) && get_msgpack_object(static_cast<std::size_t>(len));
             }
 
-            default:
+            // negative fixint
+            case 0xE0:
+            case 0xE1:
+            case 0xE2:
+            case 0xE3:
+            case 0xE4:
+            case 0xE5:
+            case 0xE6:
+            case 0xE7:
+            case 0xE8:
+            case 0xE9:
+            case 0xEA:
+            case 0xEB:
+            case 0xEC:
+            case 0xED:
+            case 0xEE:
+            case 0xEF:
+            case 0xF0:
+            case 0xF1:
+            case 0xF2:
+            case 0xF3:
+            case 0xF4:
+            case 0xF5:
+            case 0xF6:
+            case 0xF7:
+            case 0xF8:
+            case 0xF9:
+            case 0xFA:
+            case 0xFB:
+            case 0xFC:
+            case 0xFD:
+            case 0xFE:
+            case 0xFF:
+                return sax->number_integer(static_cast<std::int8_t>(current));
+
+            default: // anything else
             {
-                m_it.primitive_iterator = primitive_iterator_t();
-                break;
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::msgpack, "invalid byte: 0x" + last_token, "value"), BasicJsonType()));
             }
         }
     }
 
     /*!
-    @note The conventional copy constructor and copy assignment are implicitly
-          defined. Combined with the following converting constructor and
-          assignment, they support: (1) copy from iterator to iterator, (2)
-          copy from const iterator to const iterator, and (3) conversion from
-          iterator to const iterator. However conversion from const iterator
-          to iterator is not defined.
-    */
+    @brief reads a MessagePack string
 
-    /*!
-    @brief converting constructor
-    @param[in] other  non-const iterator to copy from
-    @note It is not checked whether @a other is initialized.
-    */
-    iter_impl(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) noexcept
-        : m_object(other.m_object), m_it(other.m_it) {}
+    This function first reads starting bytes to determine the expected
+    string length and then copies this number of bytes into a string.
 
-    /*!
-    @brief converting assignment
-    @param[in,out] other  non-const iterator to copy from
-    @return const/non-const iterator
-    @note It is not checked whether @a other is initialized.
-    */
-    iter_impl& operator=(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) noexcept
-    {
-        m_object = other.m_object;
-        m_it = other.m_it;
-        return *this;
-    }
+    @param[out] result  created string
 
-  private:
-    /*!
-    @brief set the iterator to the first value
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @return whether string creation completed
     */
-    void set_begin() noexcept
+    bool get_msgpack_string(string_t& result)
     {
-        assert(m_object != nullptr);
+        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::msgpack, "string")))
+        {
+            return false;
+        }
 
-        switch (m_object->m_type)
+        switch (current)
         {
-            case value_t::object:
+            // fixstr
+            case 0xA0:
+            case 0xA1:
+            case 0xA2:
+            case 0xA3:
+            case 0xA4:
+            case 0xA5:
+            case 0xA6:
+            case 0xA7:
+            case 0xA8:
+            case 0xA9:
+            case 0xAA:
+            case 0xAB:
+            case 0xAC:
+            case 0xAD:
+            case 0xAE:
+            case 0xAF:
+            case 0xB0:
+            case 0xB1:
+            case 0xB2:
+            case 0xB3:
+            case 0xB4:
+            case 0xB5:
+            case 0xB6:
+            case 0xB7:
+            case 0xB8:
+            case 0xB9:
+            case 0xBA:
+            case 0xBB:
+            case 0xBC:
+            case 0xBD:
+            case 0xBE:
+            case 0xBF:
             {
-                m_it.object_iterator = m_object->m_value.object->begin();
-                break;
+                return get_string(input_format_t::msgpack, static_cast<unsigned int>(current) & 0x1Fu, result);
             }
 
-            case value_t::array:
+            case 0xD9: // str 8
             {
-                m_it.array_iterator = m_object->m_value.array->begin();
-                break;
+                std::uint8_t len{};
+                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result);
             }
 
-            case value_t::null:
+            case 0xDA: // str 16
             {
-                // set to end so begin()==end() is true: null is empty
-                m_it.primitive_iterator.set_end();
-                break;
+                std::uint16_t len{};
+                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result);
             }
 
-            default:
+            case 0xDB: // str 32
             {
-                m_it.primitive_iterator.set_begin();
-                break;
+                std::uint32_t len{};
+                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result);
+            }
+
+            default:
+            {
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::msgpack, "expected length specification (0xA0-0xBF, 0xD9-0xDB); last byte: 0x" + last_token, "string"), BasicJsonType()));
             }
         }
     }
 
     /*!
-    @brief set the iterator past the last value
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @brief reads a MessagePack byte array
+
+    This function first reads starting bytes to determine the expected
+    byte array length and then copies this number of bytes into a byte array.
+
+    @param[out] result  created byte array
+
+    @return whether byte array creation completed
     */
-    void set_end() noexcept
+    bool get_msgpack_binary(binary_t& result)
     {
-        assert(m_object != nullptr);
+        // helper function to set the subtype
+        auto assign_and_return_true = [&result](std::int8_t subtype)
+        {
+            result.set_subtype(static_cast<std::uint8_t>(subtype));
+            return true;
+        };
 
-        switch (m_object->m_type)
+        switch (current)
         {
-            case value_t::object:
+            case 0xC4: // bin 8
             {
-                m_it.object_iterator = m_object->m_value.object->end();
-                break;
+                std::uint8_t len{};
+                return get_number(input_format_t::msgpack, len) &&
+                       get_binary(input_format_t::msgpack, len, result);
             }
 
-            case value_t::array:
+            case 0xC5: // bin 16
             {
-                m_it.array_iterator = m_object->m_value.array->end();
-                break;
+                std::uint16_t len{};
+                return get_number(input_format_t::msgpack, len) &&
+                       get_binary(input_format_t::msgpack, len, result);
             }
 
-            default:
+            case 0xC6: // bin 32
             {
-                m_it.primitive_iterator.set_end();
-                break;
+                std::uint32_t len{};
+                return get_number(input_format_t::msgpack, len) &&
+                       get_binary(input_format_t::msgpack, len, result);
             }
-        }
-    }
 
-  public:
-    /*!
-    @brief return a reference to the value pointed to by the iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    reference operator*() const
-    {
-        assert(m_object != nullptr);
+            case 0xC7: // ext 8
+            {
+                std::uint8_t len{};
+                std::int8_t subtype{};
+                return get_number(input_format_t::msgpack, len) &&
+                       get_number(input_format_t::msgpack, subtype) &&
+                       get_binary(input_format_t::msgpack, len, result) &&
+                       assign_and_return_true(subtype);
+            }
 
-        switch (m_object->m_type)
-        {
-            case value_t::object:
+            case 0xC8: // ext 16
             {
-                assert(m_it.object_iterator != m_object->m_value.object->end());
-                return m_it.object_iterator->second;
+                std::uint16_t len{};
+                std::int8_t subtype{};
+                return get_number(input_format_t::msgpack, len) &&
+                       get_number(input_format_t::msgpack, subtype) &&
+                       get_binary(input_format_t::msgpack, len, result) &&
+                       assign_and_return_true(subtype);
             }
 
-            case value_t::array:
+            case 0xC9: // ext 32
             {
-                assert(m_it.array_iterator != m_object->m_value.array->end());
-                return *m_it.array_iterator;
+                std::uint32_t len{};
+                std::int8_t subtype{};
+                return get_number(input_format_t::msgpack, len) &&
+                       get_number(input_format_t::msgpack, subtype) &&
+                       get_binary(input_format_t::msgpack, len, result) &&
+                       assign_and_return_true(subtype);
             }
 
-            case value_t::null:
-                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
+            case 0xD4: // fixext 1
+            {
+                std::int8_t subtype{};
+                return get_number(input_format_t::msgpack, subtype) &&
+                       get_binary(input_format_t::msgpack, 1, result) &&
+                       assign_and_return_true(subtype);
+            }
 
-            default:
+            case 0xD5: // fixext 2
             {
-                if (JSON_LIKELY(m_it.primitive_iterator.is_begin()))
-                {
-                    return *m_object;
-                }
+                std::int8_t subtype{};
+                return get_number(input_format_t::msgpack, subtype) &&
+                       get_binary(input_format_t::msgpack, 2, result) &&
+                       assign_and_return_true(subtype);
+            }
+
+            case 0xD6: // fixext 4
+            {
+                std::int8_t subtype{};
+                return get_number(input_format_t::msgpack, subtype) &&
+                       get_binary(input_format_t::msgpack, 4, result) &&
+                       assign_and_return_true(subtype);
+            }
+
+            case 0xD7: // fixext 8
+            {
+                std::int8_t subtype{};
+                return get_number(input_format_t::msgpack, subtype) &&
+                       get_binary(input_format_t::msgpack, 8, result) &&
+                       assign_and_return_true(subtype);
+            }
 
-                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
+            case 0xD8: // fixext 16
+            {
+                std::int8_t subtype{};
+                return get_number(input_format_t::msgpack, subtype) &&
+                       get_binary(input_format_t::msgpack, 16, result) &&
+                       assign_and_return_true(subtype);
             }
+
+            default:           // LCOV_EXCL_LINE
+                return false;  // LCOV_EXCL_LINE
         }
     }
 
     /*!
-    @brief dereference the iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @param[in] len  the length of the array
+    @return whether array creation completed
     */
-    pointer operator->() const
+    bool get_msgpack_array(const std::size_t len)
     {
-        assert(m_object != nullptr);
+        if (JSON_HEDLEY_UNLIKELY(!sax->start_array(len)))
+        {
+            return false;
+        }
 
-        switch (m_object->m_type)
+        for (std::size_t i = 0; i < len; ++i)
         {
-            case value_t::object:
+            if (JSON_HEDLEY_UNLIKELY(!parse_msgpack_internal()))
             {
-                assert(m_it.object_iterator != m_object->m_value.object->end());
-                return &(m_it.object_iterator->second);
+                return false;
             }
+        }
 
-            case value_t::array:
+        return sax->end_array();
+    }
+
+    /*!
+    @param[in] len  the length of the object
+    @return whether object creation completed
+    */
+    bool get_msgpack_object(const std::size_t len)
+    {
+        if (JSON_HEDLEY_UNLIKELY(!sax->start_object(len)))
+        {
+            return false;
+        }
+
+        string_t key;
+        for (std::size_t i = 0; i < len; ++i)
+        {
+            get();
+            if (JSON_HEDLEY_UNLIKELY(!get_msgpack_string(key) || !sax->key(key)))
             {
-                assert(m_it.array_iterator != m_object->m_value.array->end());
-                return &*m_it.array_iterator;
+                return false;
             }
 
-            default:
+            if (JSON_HEDLEY_UNLIKELY(!parse_msgpack_internal()))
             {
-                if (JSON_LIKELY(m_it.primitive_iterator.is_begin()))
-                {
-                    return m_object;
-                }
-
-                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
+                return false;
             }
+            key.clear();
         }
+
+        return sax->end_object();
     }
 
+    ////////////
+    // UBJSON //
+    ////////////
+
     /*!
-    @brief post-increment (it++)
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @param[in] get_char  whether a new character should be retrieved from the
+                         input (true, default) or whether the last read
+                         character should be considered instead
+
+    @return whether a valid UBJSON value was passed to the SAX parser
     */
-    iter_impl const operator++(int)
+    bool parse_ubjson_internal(const bool get_char = true)
     {
-        auto result = *this;
-        ++(*this);
-        return result;
+        return get_ubjson_value(get_char ? get_ignore_noop() : current);
     }
 
     /*!
-    @brief pre-increment (++it)
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @brief reads a UBJSON string
+
+    This function is either called after reading the 'S' byte explicitly
+    indicating a string, or in case of an object key where the 'S' byte can be
+    left out.
+
+    @param[out] result   created string
+    @param[in] get_char  whether a new character should be retrieved from the
+                         input (true, default) or whether the last read
+                         character should be considered instead
+
+    @return whether string creation completed
     */
-    iter_impl& operator++()
+    bool get_ubjson_string(string_t& result, const bool get_char = true)
     {
-        assert(m_object != nullptr);
+        if (get_char)
+        {
+            get();  // TODO(niels): may we ignore N here?
+        }
 
-        switch (m_object->m_type)
+        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::ubjson, "value")))
         {
-            case value_t::object:
+            return false;
+        }
+
+        switch (current)
+        {
+            case 'U':
             {
-                std::advance(m_it.object_iterator, 1);
-                break;
+                std::uint8_t len{};
+                return get_number(input_format_t::ubjson, len) && get_string(input_format_t::ubjson, len, result);
             }
 
-            case value_t::array:
+            case 'i':
             {
-                std::advance(m_it.array_iterator, 1);
-                break;
+                std::int8_t len{};
+                return get_number(input_format_t::ubjson, len) && get_string(input_format_t::ubjson, len, result);
             }
 
-            default:
+            case 'I':
             {
-                ++m_it.primitive_iterator;
-                break;
+                std::int16_t len{};
+                return get_number(input_format_t::ubjson, len) && get_string(input_format_t::ubjson, len, result);
             }
-        }
 
-        return *this;
-    }
+            case 'l':
+            {
+                std::int32_t len{};
+                return get_number(input_format_t::ubjson, len) && get_string(input_format_t::ubjson, len, result);
+            }
 
-    /*!
-    @brief post-decrement (it--)
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    iter_impl const operator--(int)
-    {
-        auto result = *this;
-        --(*this);
-        return result;
+            case 'L':
+            {
+                std::int64_t len{};
+                return get_number(input_format_t::ubjson, len) && get_string(input_format_t::ubjson, len, result);
+            }
+
+            default:
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "expected length type specification (U, i, I, l, L); last byte: 0x" + last_token, "string"), BasicJsonType()));
+        }
     }
 
     /*!
-    @brief pre-decrement (--it)
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @param[out] result  determined size
+    @return whether size determination completed
     */
-    iter_impl& operator--()
+    bool get_ubjson_size_value(std::size_t& result)
     {
-        assert(m_object != nullptr);
-
-        switch (m_object->m_type)
+        switch (get_ignore_noop())
         {
-            case value_t::object:
+            case 'U':
             {
-                std::advance(m_it.object_iterator, -1);
-                break;
+                std::uint8_t number{};
+                if (JSON_HEDLEY_UNLIKELY(!get_number(input_format_t::ubjson, number)))
+                {
+                    return false;
+                }
+                result = static_cast<std::size_t>(number);
+                return true;
             }
 
-            case value_t::array:
+            case 'i':
             {
-                std::advance(m_it.array_iterator, -1);
-                break;
+                std::int8_t number{};
+                if (JSON_HEDLEY_UNLIKELY(!get_number(input_format_t::ubjson, number)))
+                {
+                    return false;
+                }
+                result = static_cast<std::size_t>(number); // NOLINT(bugprone-signed-char-misuse,cert-str34-c): number is not a char
+                return true;
+            }
+
+            case 'I':
+            {
+                std::int16_t number{};
+                if (JSON_HEDLEY_UNLIKELY(!get_number(input_format_t::ubjson, number)))
+                {
+                    return false;
+                }
+                result = static_cast<std::size_t>(number);
+                return true;
+            }
+
+            case 'l':
+            {
+                std::int32_t number{};
+                if (JSON_HEDLEY_UNLIKELY(!get_number(input_format_t::ubjson, number)))
+                {
+                    return false;
+                }
+                result = static_cast<std::size_t>(number);
+                return true;
+            }
+
+            case 'L':
+            {
+                std::int64_t number{};
+                if (JSON_HEDLEY_UNLIKELY(!get_number(input_format_t::ubjson, number)))
+                {
+                    return false;
+                }
+                result = static_cast<std::size_t>(number);
+                return true;
             }
 
             default:
             {
-                --m_it.primitive_iterator;
-                break;
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "expected length type specification (U, i, I, l, L) after '#'; last byte: 0x" + last_token, "size"), BasicJsonType()));
             }
         }
-
-        return *this;
     }
 
     /*!
-    @brief  comparison: equal
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @brief determine the type and size for a container
+
+    In the optimized UBJSON format, a type and a size can be provided to allow
+    for a more compact representation.
+
+    @param[out] result  pair of the size and the type
+
+    @return whether pair creation completed
     */
-    bool operator==(const iter_impl& other) const
+    bool get_ubjson_size_type(std::pair<std::size_t, char_int_type>& result)
     {
-        // if objects are not the same, the comparison is undefined
-        if (JSON_UNLIKELY(m_object != other.m_object))
+        result.first = string_t::npos; // size
+        result.second = 0; // type
+
+        get_ignore_noop();
+
+        if (current == '$')
         {
-            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
-        }
+            result.second = get();  // must not ignore 'N', because 'N' maybe the type
+            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::ubjson, "type")))
+            {
+                return false;
+            }
+
+            get_ignore_noop();
+            if (JSON_HEDLEY_UNLIKELY(current != '#'))
+            {
+                if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::ubjson, "value")))
+                {
+                    return false;
+                }
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::ubjson, "expected '#' after type information; last byte: 0x" + last_token, "size"), BasicJsonType()));
+            }
 
-        assert(m_object != nullptr);
+            return get_ubjson_size_value(result.first);
+        }
 
-        switch (m_object->m_type)
+        if (current == '#')
         {
-            case value_t::object:
-                return (m_it.object_iterator == other.m_it.object_iterator);
-
-            case value_t::array:
-                return (m_it.array_iterator == other.m_it.array_iterator);
-
-            default:
-                return (m_it.primitive_iterator == other.m_it.primitive_iterator);
+            return get_ubjson_size_value(result.first);
         }
-    }
 
-    /*!
-    @brief  comparison: not equal
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    bool operator!=(const iter_impl& other) const
-    {
-        return not operator==(other);
+        return true;
     }
 
     /*!
-    @brief  comparison: smaller
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @param prefix  the previously read or set type prefix
+    @return whether value creation completed
     */
-    bool operator<(const iter_impl& other) const
+    bool get_ubjson_value(const char_int_type prefix)
     {
-        // if objects are not the same, the comparison is undefined
-        if (JSON_UNLIKELY(m_object != other.m_object))
+        switch (prefix)
         {
-            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
-        }
-
-        assert(m_object != nullptr);
+            case std::char_traits<char_type>::eof():  // EOF
+                return unexpect_eof(input_format_t::ubjson, "value");
 
-        switch (m_object->m_type)
-        {
-            case value_t::object:
-                JSON_THROW(invalid_iterator::create(213, "cannot compare order of object iterators"));
+            case 'T':  // true
+                return sax->boolean(true);
+            case 'F':  // false
+                return sax->boolean(false);
 
-            case value_t::array:
-                return (m_it.array_iterator < other.m_it.array_iterator);
+            case 'Z':  // null
+                return sax->null();
 
-            default:
-                return (m_it.primitive_iterator < other.m_it.primitive_iterator);
-        }
-    }
+            case 'U':
+            {
+                std::uint8_t number{};
+                return get_number(input_format_t::ubjson, number) && sax->number_unsigned(number);
+            }
 
-    /*!
-    @brief  comparison: less than or equal
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    bool operator<=(const iter_impl& other) const
-    {
-        return not other.operator < (*this);
-    }
+            case 'i':
+            {
+                std::int8_t number{};
+                return get_number(input_format_t::ubjson, number) && sax->number_integer(number);
+            }
 
-    /*!
-    @brief  comparison: greater than
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    bool operator>(const iter_impl& other) const
-    {
-        return not operator<=(other);
-    }
+            case 'I':
+            {
+                std::int16_t number{};
+                return get_number(input_format_t::ubjson, number) && sax->number_integer(number);
+            }
 
-    /*!
-    @brief  comparison: greater than or equal
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    bool operator>=(const iter_impl& other) const
-    {
-        return not operator<(other);
-    }
+            case 'l':
+            {
+                std::int32_t number{};
+                return get_number(input_format_t::ubjson, number) && sax->number_integer(number);
+            }
 
-    /*!
-    @brief  add to iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    iter_impl& operator+=(difference_type i)
-    {
-        assert(m_object != nullptr);
+            case 'L':
+            {
+                std::int64_t number{};
+                return get_number(input_format_t::ubjson, number) && sax->number_integer(number);
+            }
 
-        switch (m_object->m_type)
-        {
-            case value_t::object:
-                JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));
+            case 'd':
+            {
+                float number{};
+                return get_number(input_format_t::ubjson, number) && sax->number_float(static_cast<number_float_t>(number), "");
+            }
 
-            case value_t::array:
+            case 'D':
             {
-                std::advance(m_it.array_iterator, i);
-                break;
+                double number{};
+                return get_number(input_format_t::ubjson, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
-            default:
+            case 'H':
             {
-                m_it.primitive_iterator += i;
-                break;
+                return get_ubjson_high_precision_number();
             }
-        }
 
-        return *this;
-    }
+            case 'C':  // char
+            {
+                get();
+                if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::ubjson, "char")))
+                {
+                    return false;
+                }
+                if (JSON_HEDLEY_UNLIKELY(current > 127))
+                {
+                    auto last_token = get_token_string();
+                    return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "byte after 'C' must be in range 0x00..0x7F; last byte: 0x" + last_token, "char"), BasicJsonType()));
+                }
+                string_t s(1, static_cast<typename string_t::value_type>(current));
+                return sax->string(s);
+            }
 
-    /*!
-    @brief  subtract from iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    iter_impl& operator-=(difference_type i)
-    {
-        return operator+=(-i);
-    }
+            case 'S':  // string
+            {
+                string_t s;
+                return get_ubjson_string(s) && sax->string(s);
+            }
 
-    /*!
-    @brief  add to iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    iter_impl operator+(difference_type i) const
-    {
-        auto result = *this;
-        result += i;
-        return result;
-    }
+            case '[':  // array
+                return get_ubjson_array();
 
-    /*!
-    @brief  addition of distance and iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    friend iter_impl operator+(difference_type i, const iter_impl& it)
-    {
-        auto result = it;
-        result += i;
-        return result;
-    }
+            case '{':  // object
+                return get_ubjson_object();
 
-    /*!
-    @brief  subtract from iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    iter_impl operator-(difference_type i) const
-    {
-        auto result = *this;
-        result -= i;
-        return result;
+            default: // anything else
+            {
+                auto last_token = get_token_string();
+                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::ubjson, "invalid byte: 0x" + last_token, "value"), BasicJsonType()));
+            }
+        }
     }
 
     /*!
-    @brief  return difference
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @return whether array creation completed
     */
-    difference_type operator-(const iter_impl& other) const
+    bool get_ubjson_array()
     {
-        assert(m_object != nullptr);
+        std::pair<std::size_t, char_int_type> size_and_type;
+        if (JSON_HEDLEY_UNLIKELY(!get_ubjson_size_type(size_and_type)))
+        {
+            return false;
+        }
 
-        switch (m_object->m_type)
+        if (size_and_type.first != string_t::npos)
         {
-            case value_t::object:
-                JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators"));
+            if (JSON_HEDLEY_UNLIKELY(!sax->start_array(size_and_type.first)))
+            {
+                return false;
+            }
 
-            case value_t::array:
-                return m_it.array_iterator - other.m_it.array_iterator;
+            if (size_and_type.second != 0)
+            {
+                if (size_and_type.second != 'N')
+                {
+                    for (std::size_t i = 0; i < size_and_type.first; ++i)
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!get_ubjson_value(size_and_type.second)))
+                        {
+                            return false;
+                        }
+                    }
+                }
+            }
+            else
+            {
+                for (std::size_t i = 0; i < size_and_type.first; ++i)
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!parse_ubjson_internal()))
+                    {
+                        return false;
+                    }
+                }
+            }
+        }
+        else
+        {
+            if (JSON_HEDLEY_UNLIKELY(!sax->start_array(std::size_t(-1))))
+            {
+                return false;
+            }
 
-            default:
-                return m_it.primitive_iterator - other.m_it.primitive_iterator;
+            while (current != ']')
+            {
+                if (JSON_HEDLEY_UNLIKELY(!parse_ubjson_internal(false)))
+                {
+                    return false;
+                }
+                get_ignore_noop();
+            }
         }
+
+        return sax->end_array();
     }
 
     /*!
-    @brief  access to successor
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    @return whether object creation completed
     */
-    reference operator[](difference_type n) const
+    bool get_ubjson_object()
     {
-        assert(m_object != nullptr);
-
-        switch (m_object->m_type)
+        std::pair<std::size_t, char_int_type> size_and_type;
+        if (JSON_HEDLEY_UNLIKELY(!get_ubjson_size_type(size_and_type)))
         {
-            case value_t::object:
-                JSON_THROW(invalid_iterator::create(208, "cannot use operator[] for object iterators"));
+            return false;
+        }
 
-            case value_t::array:
-                return *std::next(m_it.array_iterator, n);
+        string_t key;
+        if (size_and_type.first != string_t::npos)
+        {
+            if (JSON_HEDLEY_UNLIKELY(!sax->start_object(size_and_type.first)))
+            {
+                return false;
+            }
 
-            case value_t::null:
-                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
+            if (size_and_type.second != 0)
+            {
+                for (std::size_t i = 0; i < size_and_type.first; ++i)
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!get_ubjson_string(key) || !sax->key(key)))
+                    {
+                        return false;
+                    }
+                    if (JSON_HEDLEY_UNLIKELY(!get_ubjson_value(size_and_type.second)))
+                    {
+                        return false;
+                    }
+                    key.clear();
+                }
+            }
+            else
+            {
+                for (std::size_t i = 0; i < size_and_type.first; ++i)
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!get_ubjson_string(key) || !sax->key(key)))
+                    {
+                        return false;
+                    }
+                    if (JSON_HEDLEY_UNLIKELY(!parse_ubjson_internal()))
+                    {
+                        return false;
+                    }
+                    key.clear();
+                }
+            }
+        }
+        else
+        {
+            if (JSON_HEDLEY_UNLIKELY(!sax->start_object(std::size_t(-1))))
+            {
+                return false;
+            }
 
-            default:
+            while (current != '}')
             {
-                if (JSON_LIKELY(m_it.primitive_iterator.get_value() == -n))
+                if (JSON_HEDLEY_UNLIKELY(!get_ubjson_string(key, false) || !sax->key(key)))
                 {
-                    return *m_object;
+                    return false;
                 }
-
-                JSON_THROW(invalid_iterator::create(214, "cannot get value"));
+                if (JSON_HEDLEY_UNLIKELY(!parse_ubjson_internal()))
+                {
+                    return false;
+                }
+                get_ignore_noop();
+                key.clear();
             }
         }
+
+        return sax->end_object();
     }
 
-    /*!
-    @brief  return the key of an object iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    const typename object_t::key_type& key() const
-    {
-        assert(m_object != nullptr);
+    // Note, no reader for UBJSON binary types is implemented because they do
+    // not exist
 
-        if (JSON_LIKELY(m_object->is_object()))
+    bool get_ubjson_high_precision_number()
+    {
+        // get size of following number string
+        std::size_t size{};
+        auto res = get_ubjson_size_value(size);
+        if (JSON_HEDLEY_UNLIKELY(!res))
         {
-            return m_it.object_iterator->first;
+            return res;
         }
 
-        JSON_THROW(invalid_iterator::create(207, "cannot use key() for non-object iterators"));
-    }
-
-    /*!
-    @brief  return the value of an iterator
-    @pre The iterator is initialized; i.e. `m_object != nullptr`.
-    */
-    reference value() const
-    {
-        return operator*();
-    }
-
-  private:
-    /// associated JSON instance
-    pointer m_object = nullptr;
-    /// the actual iterator of the associated instance
-    internal_iterator<typename std::remove_const<BasicJsonType>::type> m_it;
-};
-}  // namespace detail
-} // namespace nlohmann
-// #include <nlohmann/detail/iterators/iteration_proxy.hpp>
-
-// #include <nlohmann/detail/iterators/json_reverse_iterator.hpp>
-
-
-#include <cstddef> // ptrdiff_t
-#include <iterator> // reverse_iterator
-#include <utility> // declval
-
-namespace nlohmann
-{
-namespace detail
-{
-//////////////////////
-// reverse_iterator //
-//////////////////////
-
-/*!
-@brief a template for a reverse iterator class
-
-@tparam Base the base iterator type to reverse. Valid types are @ref
-iterator (to create @ref reverse_iterator) and @ref const_iterator (to
-create @ref const_reverse_iterator).
-
-@requirement The class satisfies the following concept requirements:
--
-[BidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator):
-  The iterator that can be moved can be moved in both directions (i.e.
-  incremented and decremented).
-- [OutputIterator](https://en.cppreference.com/w/cpp/named_req/OutputIterator):
-  It is possible to write to the pointed-to element (only if @a Base is
-  @ref iterator).
+        // get number string
+        std::vector<char> number_vector;
+        for (std::size_t i = 0; i < size; ++i)
+        {
+            get();
+            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::ubjson, "number")))
+            {
+                return false;
+            }
+            number_vector.push_back(static_cast<char>(current));
+        }
 
-@since version 1.0.0
-*/
-template<typename Base>
-class json_reverse_iterator : public std::reverse_iterator<Base>
-{
-  public:
-    using difference_type = std::ptrdiff_t;
-    /// shortcut to the reverse iterator adapter
-    using base_iterator = std::reverse_iterator<Base>;
-    /// the reference type for the pointed-to element
-    using reference = typename Base::reference;
+        // parse number string
+        using ia_type = decltype(detail::input_adapter(number_vector));
+        auto number_lexer = detail::lexer<BasicJsonType, ia_type>(detail::input_adapter(number_vector), false);
+        const auto result_number = number_lexer.scan();
+        const auto number_string = number_lexer.get_token_string();
+        const auto result_remainder = number_lexer.scan();
 
-    /// create reverse iterator from iterator
-    explicit json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept
-        : base_iterator(it) {}
+        using token_type = typename detail::lexer_base<BasicJsonType>::token_type;
 
-    /// create reverse iterator from base class
-    explicit json_reverse_iterator(const base_iterator& it) noexcept : base_iterator(it) {}
+        if (JSON_HEDLEY_UNLIKELY(result_remainder != token_type::end_of_input))
+        {
+            return sax->parse_error(chars_read, number_string, parse_error::create(115, chars_read, exception_message(input_format_t::ubjson, "invalid number text: " + number_lexer.get_token_string(), "high-precision number"), BasicJsonType()));
+        }
 
-    /// post-increment (it++)
-    json_reverse_iterator const operator++(int)
-    {
-        return static_cast<json_reverse_iterator>(base_iterator::operator++(1));
+        switch (result_number)
+        {
+            case token_type::value_integer:
+                return sax->number_integer(number_lexer.get_number_integer());
+            case token_type::value_unsigned:
+                return sax->number_unsigned(number_lexer.get_number_unsigned());
+            case token_type::value_float:
+                return sax->number_float(number_lexer.get_number_float(), std::move(number_string));
+            case token_type::uninitialized:
+            case token_type::literal_true:
+            case token_type::literal_false:
+            case token_type::literal_null:
+            case token_type::value_string:
+            case token_type::begin_array:
+            case token_type::begin_object:
+            case token_type::end_array:
+            case token_type::end_object:
+            case token_type::name_separator:
+            case token_type::value_separator:
+            case token_type::parse_error:
+            case token_type::end_of_input:
+            case token_type::literal_or_value:
+            default:
+                return sax->parse_error(chars_read, number_string, parse_error::create(115, chars_read, exception_message(input_format_t::ubjson, "invalid number text: " + number_lexer.get_token_string(), "high-precision number"), BasicJsonType()));
+        }
     }
 
-    /// pre-increment (++it)
-    json_reverse_iterator& operator++()
-    {
-        return static_cast<json_reverse_iterator&>(base_iterator::operator++());
-    }
+    ///////////////////////
+    // Utility functions //
+    ///////////////////////
 
-    /// post-decrement (it--)
-    json_reverse_iterator const operator--(int)
-    {
-        return static_cast<json_reverse_iterator>(base_iterator::operator--(1));
-    }
+    /*!
+    @brief get next character from the input
 
-    /// pre-decrement (--it)
-    json_reverse_iterator& operator--()
-    {
-        return static_cast<json_reverse_iterator&>(base_iterator::operator--());
-    }
+    This function provides the interface to the used input adapter. It does
+    not throw in case the input reached EOF, but returns a -'ve valued
+    `std::char_traits<char_type>::eof()` in that case.
 
-    /// add to iterator
-    json_reverse_iterator& operator+=(difference_type i)
+    @return character read from the input
+    */
+    char_int_type get()
     {
-        return static_cast<json_reverse_iterator&>(base_iterator::operator+=(i));
+        ++chars_read;
+        return current = ia.get_character();
     }
 
-    /// add to iterator
-    json_reverse_iterator operator+(difference_type i) const
+    /*!
+    @return character read from the input after ignoring all 'N' entries
+    */
+    char_int_type get_ignore_noop()
     {
-        return static_cast<json_reverse_iterator>(base_iterator::operator+(i));
-    }
+        do
+        {
+            get();
+        }
+        while (current == 'N');
 
-    /// subtract from iterator
-    json_reverse_iterator operator-(difference_type i) const
-    {
-        return static_cast<json_reverse_iterator>(base_iterator::operator-(i));
+        return current;
     }
 
-    /// return difference
-    difference_type operator-(const json_reverse_iterator& other) const
-    {
-        return base_iterator(*this) - base_iterator(other);
-    }
+    /*
+    @brief read a number from the input
 
-    /// access to successor
-    reference operator[](difference_type n) const
-    {
-        return *(this->operator+(n));
-    }
+    @tparam NumberType the type of the number
+    @param[in] format   the current format (for diagnostics)
+    @param[out] result  number of type @a NumberType
 
-    /// return the key of an object iterator
-    auto key() const -> decltype(std::declval<Base>().key())
-    {
-        auto it = --this->base();
-        return it.key();
-    }
+    @return whether conversion completed
 
-    /// return the value of an iterator
-    reference value() const
+    @note This function needs to respect the system's endianess, because
+          bytes in CBOR, MessagePack, and UBJSON are stored in network order
+          (big endian) and therefore need reordering on little endian systems.
+    */
+    template<typename NumberType, bool InputIsLittleEndian = false>
+    bool get_number(const input_format_t format, NumberType& result)
     {
-        auto it = --this->base();
-        return it.operator * ();
-    }
-};
-}  // namespace detail
-}  // namespace nlohmann
-
-// #include <nlohmann/detail/output/output_adapters.hpp>
+        // step 1: read input into array with system's byte order
+        std::array<std::uint8_t, sizeof(NumberType)> vec{};
+        for (std::size_t i = 0; i < sizeof(NumberType); ++i)
+        {
+            get();
+            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(format, "number")))
+            {
+                return false;
+            }
 
+            // reverse byte order prior to conversion if necessary
+            if (is_little_endian != InputIsLittleEndian)
+            {
+                vec[sizeof(NumberType) - i - 1] = static_cast<std::uint8_t>(current);
+            }
+            else
+            {
+                vec[i] = static_cast<std::uint8_t>(current); // LCOV_EXCL_LINE
+            }
+        }
 
-#include <algorithm> // copy
-#include <cstddef> // size_t
-#include <ios> // streamsize
-#include <iterator> // back_inserter
-#include <memory> // shared_ptr, make_shared
-#include <ostream> // basic_ostream
-#include <string> // basic_string
-#include <vector> // vector
+        // step 2: convert array into number of type T and return
+        std::memcpy(&result, vec.data(), sizeof(NumberType));
+        return true;
+    }
 
-namespace nlohmann
-{
-namespace detail
-{
-/// abstract output adapter interface
-template<typename CharType> struct output_adapter_protocol
-{
-    virtual void write_character(CharType c) = 0;
-    virtual void write_characters(const CharType* s, std::size_t length) = 0;
-    virtual ~output_adapter_protocol() = default;
-};
+    /*!
+    @brief create a string by reading characters from the input
 
-/// a type to simplify interfaces
-template<typename CharType>
-using output_adapter_t = std::shared_ptr<output_adapter_protocol<CharType>>;
+    @tparam NumberType the type of the number
+    @param[in] format the current format (for diagnostics)
+    @param[in] len number of characters to read
+    @param[out] result string created by reading @a len bytes
 
-/// output adapter for byte vectors
-template<typename CharType>
-class output_vector_adapter : public output_adapter_protocol<CharType>
-{
-  public:
-    explicit output_vector_adapter(std::vector<CharType>& vec) noexcept
-        : v(vec)
-    {}
+    @return whether string creation completed
 
-    void write_character(CharType c) override
+    @note We can not reserve @a len bytes for the result, because @a len
+          may be too large. Usually, @ref unexpect_eof() detects the end of
+          the input before we run out of string memory.
+    */
+    template<typename NumberType>
+    bool get_string(const input_format_t format,
+                    const NumberType len,
+                    string_t& result)
     {
-        v.push_back(c);
+        bool success = true;
+        for (NumberType i = 0; i < len; i++)
+        {
+            get();
+            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(format, "string")))
+            {
+                success = false;
+                break;
+            }
+            result.push_back(static_cast<typename string_t::value_type>(current));
+        }
+        return success;
     }
 
-    void write_characters(const CharType* s, std::size_t length) override
-    {
-        std::copy(s, s + length, std::back_inserter(v));
-    }
+    /*!
+    @brief create a byte array by reading bytes from the input
 
-  private:
-    std::vector<CharType>& v;
-};
+    @tparam NumberType the type of the number
+    @param[in] format the current format (for diagnostics)
+    @param[in] len number of bytes to read
+    @param[out] result byte array created by reading @a len bytes
 
-/// output adapter for output streams
-template<typename CharType>
-class output_stream_adapter : public output_adapter_protocol<CharType>
-{
-  public:
-    explicit output_stream_adapter(std::basic_ostream<CharType>& s) noexcept
-        : stream(s)
-    {}
+    @return whether byte array creation completed
 
-    void write_character(CharType c) override
+    @note We can not reserve @a len bytes for the result, because @a len
+          may be too large. Usually, @ref unexpect_eof() detects the end of
+          the input before we run out of memory.
+    */
+    template<typename NumberType>
+    bool get_binary(const input_format_t format,
+                    const NumberType len,
+                    binary_t& result)
     {
-        stream.put(c);
+        bool success = true;
+        for (NumberType i = 0; i < len; i++)
+        {
+            get();
+            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(format, "binary")))
+            {
+                success = false;
+                break;
+            }
+            result.push_back(static_cast<std::uint8_t>(current));
+        }
+        return success;
     }
 
-    void write_characters(const CharType* s, std::size_t length) override
+    /*!
+    @param[in] format   the current format (for diagnostics)
+    @param[in] context  further context information (for diagnostics)
+    @return whether the last read character is not EOF
+    */
+    JSON_HEDLEY_NON_NULL(3)
+    bool unexpect_eof(const input_format_t format, const char* context) const
     {
-        stream.write(s, static_cast<std::streamsize>(length));
+        if (JSON_HEDLEY_UNLIKELY(current == std::char_traits<char_type>::eof()))
+        {
+            return sax->parse_error(chars_read, "<end of file>",
+                                    parse_error::create(110, chars_read, exception_message(format, "unexpected end of input", context), BasicJsonType()));
+        }
+        return true;
     }
 
-  private:
-    std::basic_ostream<CharType>& stream;
-};
-
-/// output adapter for basic_string
-template<typename CharType, typename StringType = std::basic_string<CharType>>
-class output_string_adapter : public output_adapter_protocol<CharType>
-{
-  public:
-    explicit output_string_adapter(StringType& s) noexcept
-        : str(s)
-    {}
-
-    void write_character(CharType c) override
+    /*!
+    @return a string representation of the last read byte
+    */
+    std::string get_token_string() const
     {
-        str.push_back(c);
+        std::array<char, 3> cr{{}};
+        (std::snprintf)(cr.data(), cr.size(), "%.2hhX", static_cast<unsigned char>(current)); // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        return std::string{cr.data()};
     }
 
-    void write_characters(const CharType* s, std::size_t length) override
+    /*!
+    @param[in] format   the current format
+    @param[in] detail   a detailed error message
+    @param[in] context  further context information
+    @return a message string to use in the parse_error exceptions
+    */
+    std::string exception_message(const input_format_t format,
+                                  const std::string& detail,
+                                  const std::string& context) const
     {
-        str.append(s, length);
-    }
+        std::string error_msg = "syntax error while parsing ";
 
-  private:
-    StringType& str;
-};
+        switch (format)
+        {
+            case input_format_t::cbor:
+                error_msg += "CBOR";
+                break;
 
-template<typename CharType, typename StringType = std::basic_string<CharType>>
-class output_adapter
-{
-  public:
-    output_adapter(std::vector<CharType>& vec)
-        : oa(std::make_shared<output_vector_adapter<CharType>>(vec)) {}
+            case input_format_t::msgpack:
+                error_msg += "MessagePack";
+                break;
 
-    output_adapter(std::basic_ostream<CharType>& s)
-        : oa(std::make_shared<output_stream_adapter<CharType>>(s)) {}
+            case input_format_t::ubjson:
+                error_msg += "UBJSON";
+                break;
 
-    output_adapter(StringType& s)
-        : oa(std::make_shared<output_string_adapter<CharType, StringType>>(s)) {}
+            case input_format_t::bson:
+                error_msg += "BSON";
+                break;
 
-    operator output_adapter_t<CharType>()
-    {
-        return oa;
+            case input_format_t::json: // LCOV_EXCL_LINE
+            default:            // LCOV_EXCL_LINE
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+        }
+
+        return error_msg + " " + context + ": " + detail;
     }
 
   private:
-    output_adapter_t<CharType> oa = nullptr;
+    /// input adapter
+    InputAdapterType ia;
+
+    /// the current character
+    char_int_type current = std::char_traits<char_type>::eof();
+
+    /// the number of characters read
+    std::size_t chars_read = 0;
+
+    /// whether we can assume little endianess
+    const bool is_little_endian = little_endianess();
+
+    /// the SAX parser
+    json_sax_t* sax = nullptr;
 };
 }  // namespace detail
 }  // namespace nlohmann
 
-// #include <nlohmann/detail/input/binary_reader.hpp>
+// #include <nlohmann/detail/input/input_adapters.hpp>
 
+// #include <nlohmann/detail/input/lexer.hpp>
 
-#include <algorithm> // generate_n
-#include <array> // array
-#include <cassert> // assert
-#include <cmath> // ldexp
-#include <cstddef> // size_t
-#include <cstdint> // uint8_t, uint16_t, uint32_t, uint64_t
-#include <cstdio> // snprintf
-#include <cstring> // memcpy
-#include <iterator> // back_inserter
-#include <limits> // numeric_limits
-#include <string> // char_traits, string
-#include <utility> // make_pair, move
+// #include <nlohmann/detail/input/parser.hpp>
+
+
+#include <cmath> // isfinite
+#include <cstdint> // uint8_t
+#include <functional> // function
+#include <string> // string
+#include <utility> // move
+#include <vector> // vector
+
+// #include <nlohmann/detail/exceptions.hpp>
 
 // #include <nlohmann/detail/input/input_adapters.hpp>
 
 // #include <nlohmann/detail/input/json_sax.hpp>
 
-// #include <nlohmann/detail/exceptions.hpp>
+// #include <nlohmann/detail/input/lexer.hpp>
 
 // #include <nlohmann/detail/macro_scope.hpp>
 
@@ -6477,5979 +10944,6643 @@ namespace nlohmann
 {
 namespace detail
 {
-///////////////////
-// binary reader //
-///////////////////
+////////////
+// parser //
+////////////
+
+enum class parse_event_t : std::uint8_t
+{
+    /// the parser read `{` and started to process a JSON object
+    object_start,
+    /// the parser read `}` and finished processing a JSON object
+    object_end,
+    /// the parser read `[` and started to process a JSON array
+    array_start,
+    /// the parser read `]` and finished processing a JSON array
+    array_end,
+    /// the parser read a key of a value in an object
+    key,
+    /// the parser finished reading a JSON value
+    value
+};
+
+template<typename BasicJsonType>
+using parser_callback_t =
+    std::function<bool(int /*depth*/, parse_event_t /*event*/, BasicJsonType& /*parsed*/)>;
 
 /*!
-@brief deserialization of CBOR, MessagePack, and UBJSON values
+@brief syntax analysis
+
+This class implements a recursive descent parser.
 */
-template<typename BasicJsonType, typename SAX = json_sax_dom_parser<BasicJsonType>>
-class binary_reader
+template<typename BasicJsonType, typename InputAdapterType>
+class parser
 {
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
     using string_t = typename BasicJsonType::string_t;
-    using json_sax_t = SAX;
+    using lexer_t = lexer<BasicJsonType, InputAdapterType>;
+    using token_type = typename lexer_t::token_type;
 
   public:
-    /*!
-    @brief create a binary reader
-
-    @param[in] adapter  input adapter to read from
-    */
-    explicit binary_reader(input_adapter_t adapter) : ia(std::move(adapter))
+    /// a parser reading from an input adapter
+    explicit parser(InputAdapterType&& adapter,
+                    const parser_callback_t<BasicJsonType> cb = nullptr,
+                    const bool allow_exceptions_ = true,
+                    const bool skip_comments = false)
+        : callback(cb)
+        , m_lexer(std::move(adapter), skip_comments)
+        , allow_exceptions(allow_exceptions_)
     {
-        (void)detail::is_sax_static_asserts<SAX, BasicJsonType> {};
-        assert(ia);
+        // read first token
+        get_token();
     }
 
     /*!
-    @param[in] format  the binary format to parse
-    @param[in] sax_    a SAX event processor
-    @param[in] strict  whether to expect the input to be consumed completed
+    @brief public parser interface
 
-    @return
+    @param[in] strict      whether to expect the last token to be EOF
+    @param[in,out] result  parsed JSON value
+
+    @throw parse_error.101 in case of an unexpected token
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
     */
-    bool sax_parse(const input_format_t format,
-                   json_sax_t* sax_,
-                   const bool strict = true)
+    void parse(const bool strict, BasicJsonType& result)
     {
-        sax = sax_;
-        bool result = false;
-
-        switch (format)
+        if (callback)
         {
-            case input_format_t::bson:
-                result = parse_bson_internal();
-                break;
-
-            case input_format_t::cbor:
-                result = parse_cbor_internal();
-                break;
-
-            case input_format_t::msgpack:
-                result = parse_msgpack_internal();
-                break;
+            json_sax_dom_callback_parser<BasicJsonType> sdp(result, callback, allow_exceptions);
+            sax_parse_internal(&sdp);
 
-            case input_format_t::ubjson:
-                result = parse_ubjson_internal();
-                break;
+            // in strict mode, input must be completely read
+            if (strict && (get_token() != token_type::end_of_input))
+            {
+                sdp.parse_error(m_lexer.get_position(),
+                                m_lexer.get_token_string(),
+                                parse_error::create(101, m_lexer.get_position(),
+                                                    exception_message(token_type::end_of_input, "value"), BasicJsonType()));
+            }
 
-            // LCOV_EXCL_START
-            default:
-                assert(false);
-                // LCOV_EXCL_STOP
-        }
+            // in case of an error, return discarded value
+            if (sdp.is_errored())
+            {
+                result = value_t::discarded;
+                return;
+            }
 
-        // strict mode: next byte must be EOF
-        if (result and strict)
-        {
-            if (format == input_format_t::ubjson)
+            // set top-level value to null if it was discarded by the callback
+            // function
+            if (result.is_discarded())
             {
-                get_ignore_noop();
+                result = nullptr;
             }
-            else
+        }
+        else
+        {
+            json_sax_dom_parser<BasicJsonType> sdp(result, allow_exceptions);
+            sax_parse_internal(&sdp);
+
+            // in strict mode, input must be completely read
+            if (strict && (get_token() != token_type::end_of_input))
             {
-                get();
+                sdp.parse_error(m_lexer.get_position(),
+                                m_lexer.get_token_string(),
+                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_of_input, "value"), BasicJsonType()));
             }
 
-            if (JSON_UNLIKELY(current != std::char_traits<char>::eof()))
+            // in case of an error, return discarded value
+            if (sdp.is_errored())
             {
-                return sax->parse_error(chars_read, get_token_string(),
-                                        parse_error::create(110, chars_read, exception_message(format, "expected end of input; last byte: 0x" + get_token_string(), "value")));
+                result = value_t::discarded;
+                return;
             }
         }
 
-        return result;
+        result.assert_invariant();
     }
 
     /*!
-    @brief determine system byte order
-
-    @return true if and only if system's byte order is little endian
+    @brief public accept interface
 
-    @note from http://stackoverflow.com/a/1001328/266378
+    @param[in] strict  whether to expect the last token to be EOF
+    @return whether the input is a proper JSON text
     */
-    static constexpr bool little_endianess(int num = 1) noexcept
+    bool accept(const bool strict = true)
     {
-        return (*reinterpret_cast<char*>(&num) == 1);
+        json_sax_acceptor<BasicJsonType> sax_acceptor;
+        return sax_parse(&sax_acceptor, strict);
     }
 
-  private:
-    //////////
-    // BSON //
-    //////////
-
-    /*!
-    @brief Reads in a BSON-object and passes it to the SAX-parser.
-    @return whether a valid BSON-value was passed to the SAX parser
-    */
-    bool parse_bson_internal()
+    template<typename SAX>
+    JSON_HEDLEY_NON_NULL(2)
+    bool sax_parse(SAX* sax, const bool strict = true)
     {
-        std::int32_t document_size;
-        get_number<std::int32_t, true>(input_format_t::bson, document_size);
-
-        if (JSON_UNLIKELY(not sax->start_object(std::size_t(-1))))
-        {
-            return false;
-        }
+        (void)detail::is_sax_static_asserts<SAX, BasicJsonType> {};
+        const bool result = sax_parse_internal(sax);
 
-        if (JSON_UNLIKELY(not parse_bson_element_list(/*is_array*/false)))
+        // strict mode: next byte must be EOF
+        if (result && strict && (get_token() != token_type::end_of_input))
         {
-            return false;
+            return sax->parse_error(m_lexer.get_position(),
+                                    m_lexer.get_token_string(),
+                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_of_input, "value"), BasicJsonType()));
         }
 
-        return sax->end_object();
+        return result;
     }
 
-    /*!
-    @brief Parses a C-style string from the BSON input.
-    @param[in, out] result  A reference to the string variable where the read
-                            string is to be stored.
-    @return `true` if the \x00-byte indicating the end of the string was
-             encountered before the EOF; false` indicates an unexpected EOF.
-    */
-    bool get_bson_cstr(string_t& result)
+  private:
+    template<typename SAX>
+    JSON_HEDLEY_NON_NULL(2)
+    bool sax_parse_internal(SAX* sax)
     {
-        auto out = std::back_inserter(result);
+        // stack to remember the hierarchy of structured values we are parsing
+        // true = array; false = object
+        std::vector<bool> states;
+        // value to avoid a goto (see comment where set to true)
+        bool skip_to_state_evaluation = false;
+
         while (true)
         {
-            get();
-            if (JSON_UNLIKELY(not unexpect_eof(input_format_t::bson, "cstring")))
-            {
-                return false;
-            }
-            if (current == 0x00)
+            if (!skip_to_state_evaluation)
             {
-                return true;
-            }
-            *out++ = static_cast<char>(current);
-        }
+                // invariant: get_token() was called before each iteration
+                switch (last_token)
+                {
+                    case token_type::begin_object:
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!sax->start_object(std::size_t(-1))))
+                        {
+                            return false;
+                        }
 
-        return true;
-    }
+                        // closing } -> we are done
+                        if (get_token() == token_type::end_object)
+                        {
+                            if (JSON_HEDLEY_UNLIKELY(!sax->end_object()))
+                            {
+                                return false;
+                            }
+                            break;
+                        }
 
-    /*!
-    @brief Parses a zero-terminated string of length @a len from the BSON
-           input.
-    @param[in] len  The length (including the zero-byte at the end) of the
-                    string to be read.
-    @param[in, out] result  A reference to the string variable where the read
-                            string is to be stored.
-    @tparam NumberType The type of the length @a len
-    @pre len >= 1
-    @return `true` if the string was successfully parsed
-    */
-    template<typename NumberType>
-    bool get_bson_string(const NumberType len, string_t& result)
-    {
-        if (JSON_UNLIKELY(len < 1))
-        {
-            auto last_token = get_token_string();
-            return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::bson, "string length must be at least 1, is " + std::to_string(len), "string")));
-        }
+                        // parse key
+                        if (JSON_HEDLEY_UNLIKELY(last_token != token_type::value_string))
+                        {
+                            return sax->parse_error(m_lexer.get_position(),
+                                                    m_lexer.get_token_string(),
+                                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::value_string, "object key"), BasicJsonType()));
+                        }
+                        if (JSON_HEDLEY_UNLIKELY(!sax->key(m_lexer.get_string())))
+                        {
+                            return false;
+                        }
 
-        return get_string(input_format_t::bson, len - static_cast<NumberType>(1), result) and get() != std::char_traits<char>::eof();
-    }
+                        // parse separator (:)
+                        if (JSON_HEDLEY_UNLIKELY(get_token() != token_type::name_separator))
+                        {
+                            return sax->parse_error(m_lexer.get_position(),
+                                                    m_lexer.get_token_string(),
+                                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::name_separator, "object separator"), BasicJsonType()));
+                        }
 
-    /*!
-    @brief Read a BSON document element of the given @a element_type.
-    @param[in] element_type The BSON element type, c.f. http://bsonspec.org/spec.html
-    @param[in] element_type_parse_position The position in the input stream,
-               where the `element_type` was read.
-    @warning Not all BSON element types are supported yet. An unsupported
-             @a element_type will give rise to a parse_error.114:
-             Unsupported BSON record type 0x...
-    @return whether a valid BSON-object/array was passed to the SAX parser
-    */
-    bool parse_bson_element_internal(const int element_type,
-                                     const std::size_t element_type_parse_position)
-    {
-        switch (element_type)
-        {
-            case 0x01: // double
-            {
-                double number;
-                return get_number<double, true>(input_format_t::bson, number) and sax->number_float(static_cast<number_float_t>(number), "");
-            }
+                        // remember we are now inside an object
+                        states.push_back(false);
 
-            case 0x02: // string
-            {
-                std::int32_t len;
-                string_t value;
-                return get_number<std::int32_t, true>(input_format_t::bson, len) and get_bson_string(len, value) and sax->string(value);
-            }
+                        // parse values
+                        get_token();
+                        continue;
+                    }
 
-            case 0x03: // object
-            {
-                return parse_bson_internal();
-            }
+                    case token_type::begin_array:
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!sax->start_array(std::size_t(-1))))
+                        {
+                            return false;
+                        }
 
-            case 0x04: // array
-            {
-                return parse_bson_array();
-            }
+                        // closing ] -> we are done
+                        if (get_token() == token_type::end_array)
+                        {
+                            if (JSON_HEDLEY_UNLIKELY(!sax->end_array()))
+                            {
+                                return false;
+                            }
+                            break;
+                        }
 
-            case 0x08: // boolean
-            {
-                return sax->boolean(get() != 0);
-            }
+                        // remember we are now inside an array
+                        states.push_back(true);
 
-            case 0x0A: // null
-            {
-                return sax->null();
-            }
+                        // parse values (no need to call get_token)
+                        continue;
+                    }
 
-            case 0x10: // int32
+                    case token_type::value_float:
+                    {
+                        const auto res = m_lexer.get_number_float();
+
+                        if (JSON_HEDLEY_UNLIKELY(!std::isfinite(res)))
+                        {
+                            return sax->parse_error(m_lexer.get_position(),
+                                                    m_lexer.get_token_string(),
+                                                    out_of_range::create(406, "number overflow parsing '" + m_lexer.get_token_string() + "'", BasicJsonType()));
+                        }
+
+                        if (JSON_HEDLEY_UNLIKELY(!sax->number_float(res, m_lexer.get_string())))
+                        {
+                            return false;
+                        }
+
+                        break;
+                    }
+
+                    case token_type::literal_false:
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!sax->boolean(false)))
+                        {
+                            return false;
+                        }
+                        break;
+                    }
+
+                    case token_type::literal_null:
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!sax->null()))
+                        {
+                            return false;
+                        }
+                        break;
+                    }
+
+                    case token_type::literal_true:
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!sax->boolean(true)))
+                        {
+                            return false;
+                        }
+                        break;
+                    }
+
+                    case token_type::value_integer:
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!sax->number_integer(m_lexer.get_number_integer())))
+                        {
+                            return false;
+                        }
+                        break;
+                    }
+
+                    case token_type::value_string:
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!sax->string(m_lexer.get_string())))
+                        {
+                            return false;
+                        }
+                        break;
+                    }
+
+                    case token_type::value_unsigned:
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!sax->number_unsigned(m_lexer.get_number_unsigned())))
+                        {
+                            return false;
+                        }
+                        break;
+                    }
+
+                    case token_type::parse_error:
+                    {
+                        // using "uninitialized" to avoid "expected" message
+                        return sax->parse_error(m_lexer.get_position(),
+                                                m_lexer.get_token_string(),
+                                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::uninitialized, "value"), BasicJsonType()));
+                    }
+
+                    case token_type::uninitialized:
+                    case token_type::end_array:
+                    case token_type::end_object:
+                    case token_type::name_separator:
+                    case token_type::value_separator:
+                    case token_type::end_of_input:
+                    case token_type::literal_or_value:
+                    default: // the last token was unexpected
+                    {
+                        return sax->parse_error(m_lexer.get_position(),
+                                                m_lexer.get_token_string(),
+                                                parse_error::create(101, m_lexer.get_position(), exception_message(token_type::literal_or_value, "value"), BasicJsonType()));
+                    }
+                }
+            }
+            else
             {
-                std::int32_t value;
-                return get_number<std::int32_t, true>(input_format_t::bson, value) and sax->number_integer(value);
+                skip_to_state_evaluation = false;
             }
 
-            case 0x12: // int64
+            // we reached this line after we successfully parsed a value
+            if (states.empty())
             {
-                std::int64_t value;
-                return get_number<std::int64_t, true>(input_format_t::bson, value) and sax->number_integer(value);
+                // empty stack: we reached the end of the hierarchy: done
+                return true;
             }
 
-            default: // anything else not supported (yet)
+            if (states.back())  // array
             {
-                char cr[3];
-                (std::snprintf)(cr, sizeof(cr), "%.2hhX", static_cast<unsigned char>(element_type));
-                return sax->parse_error(element_type_parse_position, std::string(cr), parse_error::create(114, element_type_parse_position, "Unsupported BSON record type 0x" + std::string(cr)));
-            }
-        }
-    }
+                // comma -> next value
+                if (get_token() == token_type::value_separator)
+                {
+                    // parse a new value
+                    get_token();
+                    continue;
+                }
 
-    /*!
-    @brief Read a BSON element list (as specified in the BSON-spec)
+                // closing ]
+                if (JSON_HEDLEY_LIKELY(last_token == token_type::end_array))
+                {
+                    if (JSON_HEDLEY_UNLIKELY(!sax->end_array()))
+                    {
+                        return false;
+                    }
 
-    The same binary layout is used for objects and arrays, hence it must be
-    indicated with the argument @a is_array which one is expected
-    (true --> array, false --> object).
+                    // We are done with this array. Before we can parse a
+                    // new value, we need to evaluate the new state first.
+                    // By setting skip_to_state_evaluation to false, we
+                    // are effectively jumping to the beginning of this if.
+                    JSON_ASSERT(!states.empty());
+                    states.pop_back();
+                    skip_to_state_evaluation = true;
+                    continue;
+                }
 
-    @param[in] is_array Determines if the element list being read is to be
-                        treated as an object (@a is_array == false), or as an
-                        array (@a is_array == true).
-    @return whether a valid BSON-object/array was passed to the SAX parser
-    */
-    bool parse_bson_element_list(const bool is_array)
-    {
-        string_t key;
-        while (int element_type = get())
-        {
-            if (JSON_UNLIKELY(not unexpect_eof(input_format_t::bson, "element list")))
-            {
-                return false;
+                return sax->parse_error(m_lexer.get_position(),
+                                        m_lexer.get_token_string(),
+                                        parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_array, "array"), BasicJsonType()));
             }
 
-            const std::size_t element_type_parse_position = chars_read;
-            if (JSON_UNLIKELY(not get_bson_cstr(key)))
-            {
-                return false;
-            }
+            // states.back() is false -> object
 
-            if (not is_array)
+            // comma -> next value
+            if (get_token() == token_type::value_separator)
             {
-                if (not sax->key(key))
+                // parse key
+                if (JSON_HEDLEY_UNLIKELY(get_token() != token_type::value_string))
+                {
+                    return sax->parse_error(m_lexer.get_position(),
+                                            m_lexer.get_token_string(),
+                                            parse_error::create(101, m_lexer.get_position(), exception_message(token_type::value_string, "object key"), BasicJsonType()));
+                }
+
+                if (JSON_HEDLEY_UNLIKELY(!sax->key(m_lexer.get_string())))
                 {
                     return false;
                 }
+
+                // parse separator (:)
+                if (JSON_HEDLEY_UNLIKELY(get_token() != token_type::name_separator))
+                {
+                    return sax->parse_error(m_lexer.get_position(),
+                                            m_lexer.get_token_string(),
+                                            parse_error::create(101, m_lexer.get_position(), exception_message(token_type::name_separator, "object separator"), BasicJsonType()));
+                }
+
+                // parse values
+                get_token();
+                continue;
             }
 
-            if (JSON_UNLIKELY(not parse_bson_element_internal(element_type, element_type_parse_position)))
+            // closing }
+            if (JSON_HEDLEY_LIKELY(last_token == token_type::end_object))
             {
-                return false;
+                if (JSON_HEDLEY_UNLIKELY(!sax->end_object()))
+                {
+                    return false;
+                }
+
+                // We are done with this object. Before we can parse a
+                // new value, we need to evaluate the new state first.
+                // By setting skip_to_state_evaluation to false, we
+                // are effectively jumping to the beginning of this if.
+                JSON_ASSERT(!states.empty());
+                states.pop_back();
+                skip_to_state_evaluation = true;
+                continue;
             }
 
-            // get_bson_cstr only appends
-            key.clear();
+            return sax->parse_error(m_lexer.get_position(),
+                                    m_lexer.get_token_string(),
+                                    parse_error::create(101, m_lexer.get_position(), exception_message(token_type::end_object, "object"), BasicJsonType()));
         }
+    }
 
-        return true;
+    /// get next token from lexer
+    token_type get_token()
+    {
+        return last_token = m_lexer.scan();
     }
 
-    /*!
-    @brief Reads an array from the BSON input and passes it to the SAX-parser.
-    @return whether a valid BSON-array was passed to the SAX parser
-    */
-    bool parse_bson_array()
+    std::string exception_message(const token_type expected, const std::string& context)
     {
-        std::int32_t document_size;
-        get_number<std::int32_t, true>(input_format_t::bson, document_size);
+        std::string error_msg = "syntax error ";
 
-        if (JSON_UNLIKELY(not sax->start_array(std::size_t(-1))))
+        if (!context.empty())
         {
-            return false;
+            error_msg += "while parsing " + context + " ";
+        }
+
+        error_msg += "- ";
+
+        if (last_token == token_type::parse_error)
+        {
+            error_msg += std::string(m_lexer.get_error_message()) + "; last read: '" +
+                         m_lexer.get_token_string() + "'";
+        }
+        else
+        {
+            error_msg += "unexpected " + std::string(lexer_t::token_type_name(last_token));
         }
 
-        if (JSON_UNLIKELY(not parse_bson_element_list(/*is_array*/true)))
+        if (expected != token_type::uninitialized)
         {
-            return false;
+            error_msg += "; expected " + std::string(lexer_t::token_type_name(expected));
         }
 
-        return sax->end_array();
+        return error_msg;
     }
 
-    //////////
-    // CBOR //
-    //////////
+  private:
+    /// callback function
+    const parser_callback_t<BasicJsonType> callback = nullptr;
+    /// the type of the last read token
+    token_type last_token = token_type::uninitialized;
+    /// the lexer
+    lexer_t m_lexer;
+    /// whether to throw exceptions in case of errors
+    const bool allow_exceptions = true;
+};
 
-    /*!
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true, default) or whether the last read
-                         character should be considered instead
+}  // namespace detail
+}  // namespace nlohmann
 
-    @return whether a valid CBOR value was passed to the SAX parser
-    */
-    bool parse_cbor_internal(const bool get_char = true)
+// #include <nlohmann/detail/iterators/internal_iterator.hpp>
+
+
+// #include <nlohmann/detail/iterators/primitive_iterator.hpp>
+
+
+#include <cstddef> // ptrdiff_t
+#include <limits>  // numeric_limits
+
+// #include <nlohmann/detail/macro_scope.hpp>
+
+
+namespace nlohmann
+{
+namespace detail
+{
+/*
+@brief an iterator for primitive JSON types
+
+This class models an iterator for primitive JSON types (boolean, number,
+string). It's only purpose is to allow the iterator/const_iterator classes
+to "iterate" over primitive values. Internally, the iterator is modeled by
+a `difference_type` variable. Value begin_value (`0`) models the begin,
+end_value (`1`) models past the end.
+*/
+class primitive_iterator_t
+{
+  private:
+    using difference_type = std::ptrdiff_t;
+    static constexpr difference_type begin_value = 0;
+    static constexpr difference_type end_value = begin_value + 1;
+
+  JSON_PRIVATE_UNLESS_TESTED:
+    /// iterator as signed integer type
+    difference_type m_it = (std::numeric_limits<std::ptrdiff_t>::min)();
+
+  public:
+    constexpr difference_type get_value() const noexcept
     {
-        switch (get_char ? get() : current)
-        {
-            // EOF
-            case std::char_traits<char>::eof():
-                return unexpect_eof(input_format_t::cbor, "value");
+        return m_it;
+    }
 
-            // Integer 0x00..0x17 (0..23)
-            case 0x00:
-            case 0x01:
-            case 0x02:
-            case 0x03:
-            case 0x04:
-            case 0x05:
-            case 0x06:
-            case 0x07:
-            case 0x08:
-            case 0x09:
-            case 0x0A:
-            case 0x0B:
-            case 0x0C:
-            case 0x0D:
-            case 0x0E:
-            case 0x0F:
-            case 0x10:
-            case 0x11:
-            case 0x12:
-            case 0x13:
-            case 0x14:
-            case 0x15:
-            case 0x16:
-            case 0x17:
-                return sax->number_unsigned(static_cast<number_unsigned_t>(current));
+    /// set iterator to a defined beginning
+    void set_begin() noexcept
+    {
+        m_it = begin_value;
+    }
 
-            case 0x18: // Unsigned integer (one-byte uint8_t follows)
-            {
-                uint8_t number;
-                return get_number(input_format_t::cbor, number) and sax->number_unsigned(number);
-            }
+    /// set iterator to a defined past the end
+    void set_end() noexcept
+    {
+        m_it = end_value;
+    }
 
-            case 0x19: // Unsigned integer (two-byte uint16_t follows)
-            {
-                uint16_t number;
-                return get_number(input_format_t::cbor, number) and sax->number_unsigned(number);
-            }
+    /// return whether the iterator can be dereferenced
+    constexpr bool is_begin() const noexcept
+    {
+        return m_it == begin_value;
+    }
 
-            case 0x1A: // Unsigned integer (four-byte uint32_t follows)
-            {
-                uint32_t number;
-                return get_number(input_format_t::cbor, number) and sax->number_unsigned(number);
-            }
+    /// return whether the iterator is at end
+    constexpr bool is_end() const noexcept
+    {
+        return m_it == end_value;
+    }
 
-            case 0x1B: // Unsigned integer (eight-byte uint64_t follows)
-            {
-                uint64_t number;
-                return get_number(input_format_t::cbor, number) and sax->number_unsigned(number);
-            }
+    friend constexpr bool operator==(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it == rhs.m_it;
+    }
 
-            // Negative integer -1-0x00..-1-0x17 (-1..-24)
-            case 0x20:
-            case 0x21:
-            case 0x22:
-            case 0x23:
-            case 0x24:
-            case 0x25:
-            case 0x26:
-            case 0x27:
-            case 0x28:
-            case 0x29:
-            case 0x2A:
-            case 0x2B:
-            case 0x2C:
-            case 0x2D:
-            case 0x2E:
-            case 0x2F:
-            case 0x30:
-            case 0x31:
-            case 0x32:
-            case 0x33:
-            case 0x34:
-            case 0x35:
-            case 0x36:
-            case 0x37:
-                return sax->number_integer(static_cast<int8_t>(0x20 - 1 - current));
+    friend constexpr bool operator<(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it < rhs.m_it;
+    }
+
+    primitive_iterator_t operator+(difference_type n) noexcept
+    {
+        auto result = *this;
+        result += n;
+        return result;
+    }
+
+    friend constexpr difference_type operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept
+    {
+        return lhs.m_it - rhs.m_it;
+    }
+
+    primitive_iterator_t& operator++() noexcept
+    {
+        ++m_it;
+        return *this;
+    }
+
+    primitive_iterator_t const operator++(int) noexcept // NOLINT(readability-const-return-type)
+    {
+        auto result = *this;
+        ++m_it;
+        return result;
+    }
 
-            case 0x38: // Negative integer (one-byte uint8_t follows)
-            {
-                uint8_t number;
-                return get_number(input_format_t::cbor, number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
-            }
+    primitive_iterator_t& operator--() noexcept
+    {
+        --m_it;
+        return *this;
+    }
 
-            case 0x39: // Negative integer -1-n (two-byte uint16_t follows)
-            {
-                uint16_t number;
-                return get_number(input_format_t::cbor, number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
-            }
+    primitive_iterator_t const operator--(int) noexcept // NOLINT(readability-const-return-type)
+    {
+        auto result = *this;
+        --m_it;
+        return result;
+    }
 
-            case 0x3A: // Negative integer -1-n (four-byte uint32_t follows)
-            {
-                uint32_t number;
-                return get_number(input_format_t::cbor, number) and sax->number_integer(static_cast<number_integer_t>(-1) - number);
-            }
+    primitive_iterator_t& operator+=(difference_type n) noexcept
+    {
+        m_it += n;
+        return *this;
+    }
 
-            case 0x3B: // Negative integer -1-n (eight-byte uint64_t follows)
-            {
-                uint64_t number;
-                return get_number(input_format_t::cbor, number) and sax->number_integer(static_cast<number_integer_t>(-1)
-                        - static_cast<number_integer_t>(number));
-            }
+    primitive_iterator_t& operator-=(difference_type n) noexcept
+    {
+        m_it -= n;
+        return *this;
+    }
+};
+}  // namespace detail
+}  // namespace nlohmann
 
-            // UTF-8 string (0x00..0x17 bytes follow)
-            case 0x60:
-            case 0x61:
-            case 0x62:
-            case 0x63:
-            case 0x64:
-            case 0x65:
-            case 0x66:
-            case 0x67:
-            case 0x68:
-            case 0x69:
-            case 0x6A:
-            case 0x6B:
-            case 0x6C:
-            case 0x6D:
-            case 0x6E:
-            case 0x6F:
-            case 0x70:
-            case 0x71:
-            case 0x72:
-            case 0x73:
-            case 0x74:
-            case 0x75:
-            case 0x76:
-            case 0x77:
-            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
-            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
-            case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
-            case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
-            case 0x7F: // UTF-8 string (indefinite length)
-            {
-                string_t s;
-                return get_cbor_string(s) and sax->string(s);
-            }
 
-            // array (0x00..0x17 data items follow)
-            case 0x80:
-            case 0x81:
-            case 0x82:
-            case 0x83:
-            case 0x84:
-            case 0x85:
-            case 0x86:
-            case 0x87:
-            case 0x88:
-            case 0x89:
-            case 0x8A:
-            case 0x8B:
-            case 0x8C:
-            case 0x8D:
-            case 0x8E:
-            case 0x8F:
-            case 0x90:
-            case 0x91:
-            case 0x92:
-            case 0x93:
-            case 0x94:
-            case 0x95:
-            case 0x96:
-            case 0x97:
-                return get_cbor_array(static_cast<std::size_t>(current & 0x1F));
+namespace nlohmann
+{
+namespace detail
+{
+/*!
+@brief an iterator value
 
-            case 0x98: // array (one-byte uint8_t for n follows)
-            {
-                uint8_t len;
-                return get_number(input_format_t::cbor, len) and get_cbor_array(static_cast<std::size_t>(len));
-            }
+@note This structure could easily be a union, but MSVC currently does not allow
+unions members with complex constructors, see https://github.com/nlohmann/json/pull/105.
+*/
+template<typename BasicJsonType> struct internal_iterator
+{
+    /// iterator for JSON objects
+    typename BasicJsonType::object_t::iterator object_iterator {};
+    /// iterator for JSON arrays
+    typename BasicJsonType::array_t::iterator array_iterator {};
+    /// generic iterator for all other types
+    primitive_iterator_t primitive_iterator {};
+};
+}  // namespace detail
+}  // namespace nlohmann
 
-            case 0x99: // array (two-byte uint16_t for n follow)
-            {
-                uint16_t len;
-                return get_number(input_format_t::cbor, len) and get_cbor_array(static_cast<std::size_t>(len));
-            }
+// #include <nlohmann/detail/iterators/iter_impl.hpp>
 
-            case 0x9A: // array (four-byte uint32_t for n follow)
-            {
-                uint32_t len;
-                return get_number(input_format_t::cbor, len) and get_cbor_array(static_cast<std::size_t>(len));
-            }
 
-            case 0x9B: // array (eight-byte uint64_t for n follow)
-            {
-                uint64_t len;
-                return get_number(input_format_t::cbor, len) and get_cbor_array(static_cast<std::size_t>(len));
-            }
+#include <iterator> // iterator, random_access_iterator_tag, bidirectional_iterator_tag, advance, next
+#include <type_traits> // conditional, is_const, remove_const
 
-            case 0x9F: // array (indefinite length)
-                return get_cbor_array(std::size_t(-1));
+// #include <nlohmann/detail/exceptions.hpp>
 
-            // map (0x00..0x17 pairs of data items follow)
-            case 0xA0:
-            case 0xA1:
-            case 0xA2:
-            case 0xA3:
-            case 0xA4:
-            case 0xA5:
-            case 0xA6:
-            case 0xA7:
-            case 0xA8:
-            case 0xA9:
-            case 0xAA:
-            case 0xAB:
-            case 0xAC:
-            case 0xAD:
-            case 0xAE:
-            case 0xAF:
-            case 0xB0:
-            case 0xB1:
-            case 0xB2:
-            case 0xB3:
-            case 0xB4:
-            case 0xB5:
-            case 0xB6:
-            case 0xB7:
-                return get_cbor_object(static_cast<std::size_t>(current & 0x1F));
+// #include <nlohmann/detail/iterators/internal_iterator.hpp>
 
-            case 0xB8: // map (one-byte uint8_t for n follows)
-            {
-                uint8_t len;
-                return get_number(input_format_t::cbor, len) and get_cbor_object(static_cast<std::size_t>(len));
-            }
+// #include <nlohmann/detail/iterators/primitive_iterator.hpp>
 
-            case 0xB9: // map (two-byte uint16_t for n follow)
-            {
-                uint16_t len;
-                return get_number(input_format_t::cbor, len) and get_cbor_object(static_cast<std::size_t>(len));
-            }
+// #include <nlohmann/detail/macro_scope.hpp>
 
-            case 0xBA: // map (four-byte uint32_t for n follow)
-            {
-                uint32_t len;
-                return get_number(input_format_t::cbor, len) and get_cbor_object(static_cast<std::size_t>(len));
-            }
+// #include <nlohmann/detail/meta/cpp_future.hpp>
 
-            case 0xBB: // map (eight-byte uint64_t for n follow)
-            {
-                uint64_t len;
-                return get_number(input_format_t::cbor, len) and get_cbor_object(static_cast<std::size_t>(len));
-            }
+// #include <nlohmann/detail/meta/type_traits.hpp>
 
-            case 0xBF: // map (indefinite length)
-                return get_cbor_object(std::size_t(-1));
+// #include <nlohmann/detail/value_t.hpp>
 
-            case 0xF4: // false
-                return sax->boolean(false);
 
-            case 0xF5: // true
-                return sax->boolean(true);
+namespace nlohmann
+{
+namespace detail
+{
+// forward declare, to be able to friend it later on
+template<typename IteratorType> class iteration_proxy;
+template<typename IteratorType> class iteration_proxy_value;
 
-            case 0xF6: // null
-                return sax->null();
+/*!
+@brief a template for a bidirectional iterator for the @ref basic_json class
+This class implements a both iterators (iterator and const_iterator) for the
+@ref basic_json class.
+@note An iterator is called *initialized* when a pointer to a JSON value has
+      been set (e.g., by a constructor or a copy assignment). If the iterator is
+      default-constructed, it is *uninitialized* and most methods are undefined.
+      **The library uses assertions to detect calls on uninitialized iterators.**
+@requirement The class satisfies the following concept requirements:
+-
+[BidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator):
+  The iterator that can be moved can be moved in both directions (i.e.
+  incremented and decremented).
+@since version 1.0.0, simplified in version 2.0.9, change to bidirectional
+       iterators in version 3.0.0 (see https://github.com/nlohmann/json/issues/593)
+*/
+template<typename BasicJsonType>
+class iter_impl
+{
+    /// the iterator with BasicJsonType of different const-ness
+    using other_iter_impl = iter_impl<typename std::conditional<std::is_const<BasicJsonType>::value, typename std::remove_const<BasicJsonType>::type, const BasicJsonType>::type>;
+    /// allow basic_json to access private members
+    friend other_iter_impl;
+    friend BasicJsonType;
+    friend iteration_proxy<iter_impl>;
+    friend iteration_proxy_value<iter_impl>;
 
-            case 0xF9: // Half-Precision Float (two-byte IEEE 754)
-            {
-                const int byte1_raw = get();
-                if (JSON_UNLIKELY(not unexpect_eof(input_format_t::cbor, "number")))
-                {
-                    return false;
-                }
-                const int byte2_raw = get();
-                if (JSON_UNLIKELY(not unexpect_eof(input_format_t::cbor, "number")))
-                {
-                    return false;
-                }
+    using object_t = typename BasicJsonType::object_t;
+    using array_t = typename BasicJsonType::array_t;
+    // make sure BasicJsonType is basic_json or const basic_json
+    static_assert(is_basic_json<typename std::remove_const<BasicJsonType>::type>::value,
+                  "iter_impl only accepts (const) basic_json");
 
-                const auto byte1 = static_cast<unsigned char>(byte1_raw);
-                const auto byte2 = static_cast<unsigned char>(byte2_raw);
+  public:
 
-                // code from RFC 7049, Appendix D, Figure 3:
-                // As half-precision floating-point numbers were only added
-                // to IEEE 754 in 2008, today's programming platforms often
-                // still only have limited support for them. It is very
-                // easy to include at least decoding support for them even
-                // without such support. An example of a small decoder for
-                // half-precision floating-point numbers in the C language
-                // is shown in Fig. 3.
-                const int half = (byte1 << 8) + byte2;
-                const double val = [&half]
-                {
-                    const int exp = (half >> 10) & 0x1F;
-                    const int mant = half & 0x3FF;
-                    assert(0 <= exp and exp <= 32);
-                    assert(0 <= mant and mant <= 1024);
-                    switch (exp)
-                    {
-                        case 0:
-                            return std::ldexp(mant, -24);
-                        case 31:
-                            return (mant == 0)
-                            ? std::numeric_limits<double>::infinity()
-                            : std::numeric_limits<double>::quiet_NaN();
-                        default:
-                            return std::ldexp(mant + 1024, exp - 25);
-                    }
-                }();
-                return sax->number_float((half & 0x8000) != 0
-                                         ? static_cast<number_float_t>(-val)
-                                         : static_cast<number_float_t>(val), "");
-            }
+    /// The std::iterator class template (used as a base class to provide typedefs) is deprecated in C++17.
+    /// The C++ Standard has never required user-defined iterators to derive from std::iterator.
+    /// A user-defined iterator should provide publicly accessible typedefs named
+    /// iterator_category, value_type, difference_type, pointer, and reference.
+    /// Note that value_type is required to be non-const, even for constant iterators.
+    using iterator_category = std::bidirectional_iterator_tag;
 
-            case 0xFA: // Single-Precision Float (four-byte IEEE 754)
+    /// the type of the values when the iterator is dereferenced
+    using value_type = typename BasicJsonType::value_type;
+    /// a type to represent differences between iterators
+    using difference_type = typename BasicJsonType::difference_type;
+    /// defines a pointer to the type iterated over (value_type)
+    using pointer = typename std::conditional<std::is_const<BasicJsonType>::value,
+          typename BasicJsonType::const_pointer,
+          typename BasicJsonType::pointer>::type;
+    /// defines a reference to the type iterated over (value_type)
+    using reference =
+        typename std::conditional<std::is_const<BasicJsonType>::value,
+        typename BasicJsonType::const_reference,
+        typename BasicJsonType::reference>::type;
+
+    iter_impl() = default;
+    ~iter_impl() = default;
+    iter_impl(iter_impl&&) noexcept = default;
+    iter_impl& operator=(iter_impl&&) noexcept = default;
+
+    /*!
+    @brief constructor for a given JSON instance
+    @param[in] object  pointer to a JSON object for this iterator
+    @pre object != nullptr
+    @post The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    explicit iter_impl(pointer object) noexcept : m_object(object)
+    {
+        JSON_ASSERT(m_object != nullptr);
+
+        switch (m_object->m_type)
+        {
+            case value_t::object:
             {
-                float number;
-                return get_number(input_format_t::cbor, number) and sax->number_float(static_cast<number_float_t>(number), "");
+                m_it.object_iterator = typename object_t::iterator();
+                break;
             }
 
-            case 0xFB: // Double-Precision Float (eight-byte IEEE 754)
+            case value_t::array:
             {
-                double number;
-                return get_number(input_format_t::cbor, number) and sax->number_float(static_cast<number_float_t>(number), "");
+                m_it.array_iterator = typename array_t::iterator();
+                break;
             }
 
-            default: // anything else (0xFF is handled inside the other types)
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
             {
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::cbor, "invalid byte: 0x" + last_token, "value")));
+                m_it.primitive_iterator = primitive_iterator_t();
+                break;
             }
         }
     }
 
     /*!
-    @brief reads a CBOR string
-
-    This function first reads starting bytes to determine the expected
-    string length and then copies this number of bytes into a string.
-    Additionally, CBOR's strings with indefinite lengths are supported.
+    @note The conventional copy constructor and copy assignment are implicitly
+          defined. Combined with the following converting constructor and
+          assignment, they support: (1) copy from iterator to iterator, (2)
+          copy from const iterator to const iterator, and (3) conversion from
+          iterator to const iterator. However conversion from const iterator
+          to iterator is not defined.
+    */
 
-    @param[out] result  created string
+    /*!
+    @brief const copy constructor
+    @param[in] other const iterator to copy from
+    @note This copy constructor had to be defined explicitly to circumvent a bug
+          occurring on msvc v19.0 compiler (VS 2015) debug build. For more
+          information refer to: https://github.com/nlohmann/json/issues/1608
+    */
+    iter_impl(const iter_impl<const BasicJsonType>& other) noexcept
+        : m_object(other.m_object), m_it(other.m_it)
+    {}
 
-    @return whether string creation completed
+    /*!
+    @brief converting assignment
+    @param[in] other const iterator to copy from
+    @return const/non-const iterator
+    @note It is not checked whether @a other is initialized.
     */
-    bool get_cbor_string(string_t& result)
+    iter_impl& operator=(const iter_impl<const BasicJsonType>& other) noexcept
     {
-        if (JSON_UNLIKELY(not unexpect_eof(input_format_t::cbor, "string")))
+        if (&other != this)
         {
-            return false;
+            m_object = other.m_object;
+            m_it = other.m_it;
         }
+        return *this;
+    }
 
-        switch (current)
-        {
-            // UTF-8 string (0x00..0x17 bytes follow)
-            case 0x60:
-            case 0x61:
-            case 0x62:
-            case 0x63:
-            case 0x64:
-            case 0x65:
-            case 0x66:
-            case 0x67:
-            case 0x68:
-            case 0x69:
-            case 0x6A:
-            case 0x6B:
-            case 0x6C:
-            case 0x6D:
-            case 0x6E:
-            case 0x6F:
-            case 0x70:
-            case 0x71:
-            case 0x72:
-            case 0x73:
-            case 0x74:
-            case 0x75:
-            case 0x76:
-            case 0x77:
-            {
-                return get_string(input_format_t::cbor, current & 0x1F, result);
-            }
+    /*!
+    @brief converting constructor
+    @param[in] other  non-const iterator to copy from
+    @note It is not checked whether @a other is initialized.
+    */
+    iter_impl(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) noexcept
+        : m_object(other.m_object), m_it(other.m_it)
+    {}
 
-            case 0x78: // UTF-8 string (one-byte uint8_t for n follows)
-            {
-                uint8_t len;
-                return get_number(input_format_t::cbor, len) and get_string(input_format_t::cbor, len, result);
-            }
+    /*!
+    @brief converting assignment
+    @param[in] other  non-const iterator to copy from
+    @return const/non-const iterator
+    @note It is not checked whether @a other is initialized.
+    */
+    iter_impl& operator=(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) noexcept // NOLINT(cert-oop54-cpp)
+    {
+        m_object = other.m_object;
+        m_it = other.m_it;
+        return *this;
+    }
 
-            case 0x79: // UTF-8 string (two-byte uint16_t for n follow)
-            {
-                uint16_t len;
-                return get_number(input_format_t::cbor, len) and get_string(input_format_t::cbor, len, result);
-            }
+  JSON_PRIVATE_UNLESS_TESTED:
+    /*!
+    @brief set the iterator to the first value
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    void set_begin() noexcept
+    {
+        JSON_ASSERT(m_object != nullptr);
 
-            case 0x7A: // UTF-8 string (four-byte uint32_t for n follow)
+        switch (m_object->m_type)
+        {
+            case value_t::object:
             {
-                uint32_t len;
-                return get_number(input_format_t::cbor, len) and get_string(input_format_t::cbor, len, result);
+                m_it.object_iterator = m_object->m_value.object->begin();
+                break;
             }
 
-            case 0x7B: // UTF-8 string (eight-byte uint64_t for n follow)
+            case value_t::array:
             {
-                uint64_t len;
-                return get_number(input_format_t::cbor, len) and get_string(input_format_t::cbor, len, result);
+                m_it.array_iterator = m_object->m_value.array->begin();
+                break;
             }
 
-            case 0x7F: // UTF-8 string (indefinite length)
+            case value_t::null:
             {
-                while (get() != 0xFF)
-                {
-                    string_t chunk;
-                    if (not get_cbor_string(chunk))
-                    {
-                        return false;
-                    }
-                    result.append(chunk);
-                }
-                return true;
+                // set to end so begin()==end() is true: null is empty
+                m_it.primitive_iterator.set_end();
+                break;
             }
 
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
             default:
             {
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::cbor, "expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0x" + last_token, "string")));
+                m_it.primitive_iterator.set_begin();
+                break;
             }
         }
     }
 
     /*!
-    @param[in] len  the length of the array or std::size_t(-1) for an
-                    array of indefinite size
-    @return whether array creation completed
+    @brief set the iterator past the last value
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool get_cbor_array(const std::size_t len)
+    void set_end() noexcept
     {
-        if (JSON_UNLIKELY(not sax->start_array(len)))
-        {
-            return false;
-        }
+        JSON_ASSERT(m_object != nullptr);
 
-        if (len != std::size_t(-1))
+        switch (m_object->m_type)
         {
-            for (std::size_t i = 0; i < len; ++i)
+            case value_t::object:
             {
-                if (JSON_UNLIKELY(not parse_cbor_internal()))
-                {
-                    return false;
-                }
+                m_it.object_iterator = m_object->m_value.object->end();
+                break;
             }
-        }
-        else
-        {
-            while (get() != 0xFF)
+
+            case value_t::array:
             {
-                if (JSON_UNLIKELY(not parse_cbor_internal(false)))
-                {
-                    return false;
-                }
+                m_it.array_iterator = m_object->m_value.array->end();
+                break;
             }
-        }
 
-        return sax->end_array();
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+            {
+                m_it.primitive_iterator.set_end();
+                break;
+            }
+        }
     }
 
+  public:
     /*!
-    @param[in] len  the length of the object or std::size_t(-1) for an
-                    object of indefinite size
-    @return whether object creation completed
+    @brief return a reference to the value pointed to by the iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool get_cbor_object(const std::size_t len)
+    reference operator*() const
     {
-        if (not JSON_UNLIKELY(sax->start_object(len)))
-        {
-            return false;
-        }
+        JSON_ASSERT(m_object != nullptr);
 
-        string_t key;
-        if (len != std::size_t(-1))
+        switch (m_object->m_type)
         {
-            for (std::size_t i = 0; i < len; ++i)
+            case value_t::object:
             {
-                get();
-                if (JSON_UNLIKELY(not get_cbor_string(key) or not sax->key(key)))
-                {
-                    return false;
-                }
-
-                if (JSON_UNLIKELY(not parse_cbor_internal()))
-                {
-                    return false;
-                }
-                key.clear();
+                JSON_ASSERT(m_it.object_iterator != m_object->m_value.object->end());
+                return m_it.object_iterator->second;
             }
-        }
-        else
-        {
-            while (get() != 0xFF)
+
+            case value_t::array:
             {
-                if (JSON_UNLIKELY(not get_cbor_string(key) or not sax->key(key)))
-                {
-                    return false;
-                }
+                JSON_ASSERT(m_it.array_iterator != m_object->m_value.array->end());
+                return *m_it.array_iterator;
+            }
+
+            case value_t::null:
+                JSON_THROW(invalid_iterator::create(214, "cannot get value", *m_object));
 
-                if (JSON_UNLIKELY(not parse_cbor_internal()))
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+            {
+                if (JSON_HEDLEY_LIKELY(m_it.primitive_iterator.is_begin()))
                 {
-                    return false;
+                    return *m_object;
                 }
-                key.clear();
+
+                JSON_THROW(invalid_iterator::create(214, "cannot get value", *m_object));
             }
         }
-
-        return sax->end_object();
     }
 
-    /////////////
-    // MsgPack //
-    /////////////
-
     /*!
-    @return whether a valid MessagePack value was passed to the SAX parser
+    @brief dereference the iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool parse_msgpack_internal()
+    pointer operator->() const
     {
-        switch (get())
-        {
-            // EOF
-            case std::char_traits<char>::eof():
-                return unexpect_eof(input_format_t::msgpack, "value");
-
-            // positive fixint
-            case 0x00:
-            case 0x01:
-            case 0x02:
-            case 0x03:
-            case 0x04:
-            case 0x05:
-            case 0x06:
-            case 0x07:
-            case 0x08:
-            case 0x09:
-            case 0x0A:
-            case 0x0B:
-            case 0x0C:
-            case 0x0D:
-            case 0x0E:
-            case 0x0F:
-            case 0x10:
-            case 0x11:
-            case 0x12:
-            case 0x13:
-            case 0x14:
-            case 0x15:
-            case 0x16:
-            case 0x17:
-            case 0x18:
-            case 0x19:
-            case 0x1A:
-            case 0x1B:
-            case 0x1C:
-            case 0x1D:
-            case 0x1E:
-            case 0x1F:
-            case 0x20:
-            case 0x21:
-            case 0x22:
-            case 0x23:
-            case 0x24:
-            case 0x25:
-            case 0x26:
-            case 0x27:
-            case 0x28:
-            case 0x29:
-            case 0x2A:
-            case 0x2B:
-            case 0x2C:
-            case 0x2D:
-            case 0x2E:
-            case 0x2F:
-            case 0x30:
-            case 0x31:
-            case 0x32:
-            case 0x33:
-            case 0x34:
-            case 0x35:
-            case 0x36:
-            case 0x37:
-            case 0x38:
-            case 0x39:
-            case 0x3A:
-            case 0x3B:
-            case 0x3C:
-            case 0x3D:
-            case 0x3E:
-            case 0x3F:
-            case 0x40:
-            case 0x41:
-            case 0x42:
-            case 0x43:
-            case 0x44:
-            case 0x45:
-            case 0x46:
-            case 0x47:
-            case 0x48:
-            case 0x49:
-            case 0x4A:
-            case 0x4B:
-            case 0x4C:
-            case 0x4D:
-            case 0x4E:
-            case 0x4F:
-            case 0x50:
-            case 0x51:
-            case 0x52:
-            case 0x53:
-            case 0x54:
-            case 0x55:
-            case 0x56:
-            case 0x57:
-            case 0x58:
-            case 0x59:
-            case 0x5A:
-            case 0x5B:
-            case 0x5C:
-            case 0x5D:
-            case 0x5E:
-            case 0x5F:
-            case 0x60:
-            case 0x61:
-            case 0x62:
-            case 0x63:
-            case 0x64:
-            case 0x65:
-            case 0x66:
-            case 0x67:
-            case 0x68:
-            case 0x69:
-            case 0x6A:
-            case 0x6B:
-            case 0x6C:
-            case 0x6D:
-            case 0x6E:
-            case 0x6F:
-            case 0x70:
-            case 0x71:
-            case 0x72:
-            case 0x73:
-            case 0x74:
-            case 0x75:
-            case 0x76:
-            case 0x77:
-            case 0x78:
-            case 0x79:
-            case 0x7A:
-            case 0x7B:
-            case 0x7C:
-            case 0x7D:
-            case 0x7E:
-            case 0x7F:
-                return sax->number_unsigned(static_cast<number_unsigned_t>(current));
-
-            // fixmap
-            case 0x80:
-            case 0x81:
-            case 0x82:
-            case 0x83:
-            case 0x84:
-            case 0x85:
-            case 0x86:
-            case 0x87:
-            case 0x88:
-            case 0x89:
-            case 0x8A:
-            case 0x8B:
-            case 0x8C:
-            case 0x8D:
-            case 0x8E:
-            case 0x8F:
-                return get_msgpack_object(static_cast<std::size_t>(current & 0x0F));
-
-            // fixarray
-            case 0x90:
-            case 0x91:
-            case 0x92:
-            case 0x93:
-            case 0x94:
-            case 0x95:
-            case 0x96:
-            case 0x97:
-            case 0x98:
-            case 0x99:
-            case 0x9A:
-            case 0x9B:
-            case 0x9C:
-            case 0x9D:
-            case 0x9E:
-            case 0x9F:
-                return get_msgpack_array(static_cast<std::size_t>(current & 0x0F));
+        JSON_ASSERT(m_object != nullptr);
 
-            // fixstr
-            case 0xA0:
-            case 0xA1:
-            case 0xA2:
-            case 0xA3:
-            case 0xA4:
-            case 0xA5:
-            case 0xA6:
-            case 0xA7:
-            case 0xA8:
-            case 0xA9:
-            case 0xAA:
-            case 0xAB:
-            case 0xAC:
-            case 0xAD:
-            case 0xAE:
-            case 0xAF:
-            case 0xB0:
-            case 0xB1:
-            case 0xB2:
-            case 0xB3:
-            case 0xB4:
-            case 0xB5:
-            case 0xB6:
-            case 0xB7:
-            case 0xB8:
-            case 0xB9:
-            case 0xBA:
-            case 0xBB:
-            case 0xBC:
-            case 0xBD:
-            case 0xBE:
-            case 0xBF:
+        switch (m_object->m_type)
+        {
+            case value_t::object:
             {
-                string_t s;
-                return get_msgpack_string(s) and sax->string(s);
+                JSON_ASSERT(m_it.object_iterator != m_object->m_value.object->end());
+                return &(m_it.object_iterator->second);
             }
 
-            case 0xC0: // nil
-                return sax->null();
-
-            case 0xC2: // false
-                return sax->boolean(false);
-
-            case 0xC3: // true
-                return sax->boolean(true);
+            case value_t::array:
+            {
+                JSON_ASSERT(m_it.array_iterator != m_object->m_value.array->end());
+                return &*m_it.array_iterator;
+            }
 
-            case 0xCA: // float 32
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
             {
-                float number;
-                return get_number(input_format_t::msgpack, number) and sax->number_float(static_cast<number_float_t>(number), "");
+                if (JSON_HEDLEY_LIKELY(m_it.primitive_iterator.is_begin()))
+                {
+                    return m_object;
+                }
+
+                JSON_THROW(invalid_iterator::create(214, "cannot get value", *m_object));
             }
+        }
+    }
+
+    /*!
+    @brief post-increment (it++)
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl const operator++(int) // NOLINT(readability-const-return-type)
+    {
+        auto result = *this;
+        ++(*this);
+        return result;
+    }
 
-            case 0xCB: // float 64
-            {
-                double number;
-                return get_number(input_format_t::msgpack, number) and sax->number_float(static_cast<number_float_t>(number), "");
-            }
+    /*!
+    @brief pre-increment (++it)
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl& operator++()
+    {
+        JSON_ASSERT(m_object != nullptr);
 
-            case 0xCC: // uint 8
+        switch (m_object->m_type)
+        {
+            case value_t::object:
             {
-                uint8_t number;
-                return get_number(input_format_t::msgpack, number) and sax->number_unsigned(number);
+                std::advance(m_it.object_iterator, 1);
+                break;
             }
 
-            case 0xCD: // uint 16
+            case value_t::array:
             {
-                uint16_t number;
-                return get_number(input_format_t::msgpack, number) and sax->number_unsigned(number);
+                std::advance(m_it.array_iterator, 1);
+                break;
             }
 
-            case 0xCE: // uint 32
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
             {
-                uint32_t number;
-                return get_number(input_format_t::msgpack, number) and sax->number_unsigned(number);
+                ++m_it.primitive_iterator;
+                break;
             }
+        }
 
-            case 0xCF: // uint 64
-            {
-                uint64_t number;
-                return get_number(input_format_t::msgpack, number) and sax->number_unsigned(number);
-            }
+        return *this;
+    }
 
-            case 0xD0: // int 8
-            {
-                int8_t number;
-                return get_number(input_format_t::msgpack, number) and sax->number_integer(number);
-            }
+    /*!
+    @brief post-decrement (it--)
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl const operator--(int) // NOLINT(readability-const-return-type)
+    {
+        auto result = *this;
+        --(*this);
+        return result;
+    }
 
-            case 0xD1: // int 16
-            {
-                int16_t number;
-                return get_number(input_format_t::msgpack, number) and sax->number_integer(number);
-            }
+    /*!
+    @brief pre-decrement (--it)
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl& operator--()
+    {
+        JSON_ASSERT(m_object != nullptr);
 
-            case 0xD2: // int 32
+        switch (m_object->m_type)
+        {
+            case value_t::object:
             {
-                int32_t number;
-                return get_number(input_format_t::msgpack, number) and sax->number_integer(number);
+                std::advance(m_it.object_iterator, -1);
+                break;
             }
 
-            case 0xD3: // int 64
+            case value_t::array:
             {
-                int64_t number;
-                return get_number(input_format_t::msgpack, number) and sax->number_integer(number);
+                std::advance(m_it.array_iterator, -1);
+                break;
             }
 
-            case 0xD9: // str 8
-            case 0xDA: // str 16
-            case 0xDB: // str 32
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
             {
-                string_t s;
-                return get_msgpack_string(s) and sax->string(s);
+                --m_it.primitive_iterator;
+                break;
             }
+        }
 
-            case 0xDC: // array 16
-            {
-                uint16_t len;
-                return get_number(input_format_t::msgpack, len) and get_msgpack_array(static_cast<std::size_t>(len));
-            }
+        return *this;
+    }
 
-            case 0xDD: // array 32
-            {
-                uint32_t len;
-                return get_number(input_format_t::msgpack, len) and get_msgpack_array(static_cast<std::size_t>(len));
-            }
+    /*!
+    @brief comparison: equal
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    template < typename IterImpl, detail::enable_if_t < (std::is_same<IterImpl, iter_impl>::value || std::is_same<IterImpl, other_iter_impl>::value), std::nullptr_t > = nullptr >
+    bool operator==(const IterImpl& other) const
+    {
+        // if objects are not the same, the comparison is undefined
+        if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
+        {
+            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers", *m_object));
+        }
 
-            case 0xDE: // map 16
-            {
-                uint16_t len;
-                return get_number(input_format_t::msgpack, len) and get_msgpack_object(static_cast<std::size_t>(len));
-            }
+        JSON_ASSERT(m_object != nullptr);
 
-            case 0xDF: // map 32
-            {
-                uint32_t len;
-                return get_number(input_format_t::msgpack, len) and get_msgpack_object(static_cast<std::size_t>(len));
-            }
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+                return (m_it.object_iterator == other.m_it.object_iterator);
 
-            // negative fixint
-            case 0xE0:
-            case 0xE1:
-            case 0xE2:
-            case 0xE3:
-            case 0xE4:
-            case 0xE5:
-            case 0xE6:
-            case 0xE7:
-            case 0xE8:
-            case 0xE9:
-            case 0xEA:
-            case 0xEB:
-            case 0xEC:
-            case 0xED:
-            case 0xEE:
-            case 0xEF:
-            case 0xF0:
-            case 0xF1:
-            case 0xF2:
-            case 0xF3:
-            case 0xF4:
-            case 0xF5:
-            case 0xF6:
-            case 0xF7:
-            case 0xF8:
-            case 0xF9:
-            case 0xFA:
-            case 0xFB:
-            case 0xFC:
-            case 0xFD:
-            case 0xFE:
-            case 0xFF:
-                return sax->number_integer(static_cast<int8_t>(current));
+            case value_t::array:
+                return (m_it.array_iterator == other.m_it.array_iterator);
 
-            default: // anything else
-            {
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::msgpack, "invalid byte: 0x" + last_token, "value")));
-            }
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+                return (m_it.primitive_iterator == other.m_it.primitive_iterator);
         }
     }
 
     /*!
-    @brief reads a MessagePack string
-
-    This function first reads starting bytes to determine the expected
-    string length and then copies this number of bytes into a string.
-
-    @param[out] result  created string
+    @brief comparison: not equal
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    template < typename IterImpl, detail::enable_if_t < (std::is_same<IterImpl, iter_impl>::value || std::is_same<IterImpl, other_iter_impl>::value), std::nullptr_t > = nullptr >
+    bool operator!=(const IterImpl& other) const
+    {
+        return !operator==(other);
+    }
 
-    @return whether string creation completed
+    /*!
+    @brief comparison: smaller
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool get_msgpack_string(string_t& result)
+    bool operator<(const iter_impl& other) const
     {
-        if (JSON_UNLIKELY(not unexpect_eof(input_format_t::msgpack, "string")))
+        // if objects are not the same, the comparison is undefined
+        if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
         {
-            return false;
+            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers", *m_object));
         }
 
-        switch (current)
-        {
-            // fixstr
-            case 0xA0:
-            case 0xA1:
-            case 0xA2:
-            case 0xA3:
-            case 0xA4:
-            case 0xA5:
-            case 0xA6:
-            case 0xA7:
-            case 0xA8:
-            case 0xA9:
-            case 0xAA:
-            case 0xAB:
-            case 0xAC:
-            case 0xAD:
-            case 0xAE:
-            case 0xAF:
-            case 0xB0:
-            case 0xB1:
-            case 0xB2:
-            case 0xB3:
-            case 0xB4:
-            case 0xB5:
-            case 0xB6:
-            case 0xB7:
-            case 0xB8:
-            case 0xB9:
-            case 0xBA:
-            case 0xBB:
-            case 0xBC:
-            case 0xBD:
-            case 0xBE:
-            case 0xBF:
-            {
-                return get_string(input_format_t::msgpack, current & 0x1F, result);
-            }
-
-            case 0xD9: // str 8
-            {
-                uint8_t len;
-                return get_number(input_format_t::msgpack, len) and get_string(input_format_t::msgpack, len, result);
-            }
+        JSON_ASSERT(m_object != nullptr);
 
-            case 0xDA: // str 16
-            {
-                uint16_t len;
-                return get_number(input_format_t::msgpack, len) and get_string(input_format_t::msgpack, len, result);
-            }
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+                JSON_THROW(invalid_iterator::create(213, "cannot compare order of object iterators", *m_object));
 
-            case 0xDB: // str 32
-            {
-                uint32_t len;
-                return get_number(input_format_t::msgpack, len) and get_string(input_format_t::msgpack, len, result);
-            }
+            case value_t::array:
+                return (m_it.array_iterator < other.m_it.array_iterator);
 
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
             default:
-            {
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::msgpack, "expected length specification (0xA0-0xBF, 0xD9-0xDB); last byte: 0x" + last_token, "string")));
-            }
+                return (m_it.primitive_iterator < other.m_it.primitive_iterator);
         }
     }
 
     /*!
-    @param[in] len  the length of the array
-    @return whether array creation completed
+    @brief comparison: less than or equal
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    bool operator<=(const iter_impl& other) const
+    {
+        return !other.operator < (*this);
+    }
+
+    /*!
+    @brief comparison: greater than
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    bool operator>(const iter_impl& other) const
+    {
+        return !operator<=(other);
+    }
+
+    /*!
+    @brief comparison: greater than or equal
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool get_msgpack_array(const std::size_t len)
+    bool operator>=(const iter_impl& other) const
     {
-        if (JSON_UNLIKELY(not sax->start_array(len)))
-        {
-            return false;
-        }
-
-        for (std::size_t i = 0; i < len; ++i)
-        {
-            if (JSON_UNLIKELY(not parse_msgpack_internal()))
-            {
-                return false;
-            }
-        }
-
-        return sax->end_array();
+        return !operator<(other);
     }
 
     /*!
-    @param[in] len  the length of the object
-    @return whether object creation completed
+    @brief add to iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool get_msgpack_object(const std::size_t len)
+    iter_impl& operator+=(difference_type i)
     {
-        if (JSON_UNLIKELY(not sax->start_object(len)))
-        {
-            return false;
-        }
+        JSON_ASSERT(m_object != nullptr);
 
-        string_t key;
-        for (std::size_t i = 0; i < len; ++i)
+        switch (m_object->m_type)
         {
-            get();
-            if (JSON_UNLIKELY(not get_msgpack_string(key) or not sax->key(key)))
+            case value_t::object:
+                JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators", *m_object));
+
+            case value_t::array:
             {
-                return false;
+                std::advance(m_it.array_iterator, i);
+                break;
             }
 
-            if (JSON_UNLIKELY(not parse_msgpack_internal()))
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
             {
-                return false;
+                m_it.primitive_iterator += i;
+                break;
             }
-            key.clear();
         }
 
-        return sax->end_object();
+        return *this;
     }
 
-    ////////////
-    // UBJSON //
-    ////////////
-
     /*!
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true, default) or whether the last read
-                         character should be considered instead
-
-    @return whether a valid UBJSON value was passed to the SAX parser
+    @brief subtract from iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool parse_ubjson_internal(const bool get_char = true)
+    iter_impl& operator-=(difference_type i)
     {
-        return get_ubjson_value(get_char ? get_ignore_noop() : current);
+        return operator+=(-i);
     }
 
     /*!
-    @brief reads a UBJSON string
+    @brief add to iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl operator+(difference_type i) const
+    {
+        auto result = *this;
+        result += i;
+        return result;
+    }
 
-    This function is either called after reading the 'S' byte explicitly
-    indicating a string, or in case of an object key where the 'S' byte can be
-    left out.
+    /*!
+    @brief addition of distance and iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    friend iter_impl operator+(difference_type i, const iter_impl& it)
+    {
+        auto result = it;
+        result += i;
+        return result;
+    }
 
-    @param[out] result   created string
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true, default) or whether the last read
-                         character should be considered instead
+    /*!
+    @brief subtract from iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    iter_impl operator-(difference_type i) const
+    {
+        auto result = *this;
+        result -= i;
+        return result;
+    }
 
-    @return whether string creation completed
+    /*!
+    @brief return difference
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool get_ubjson_string(string_t& result, const bool get_char = true)
+    difference_type operator-(const iter_impl& other) const
     {
-        if (get_char)
-        {
-            get();  // TODO: may we ignore N here?
-        }
+        JSON_ASSERT(m_object != nullptr);
 
-        if (JSON_UNLIKELY(not unexpect_eof(input_format_t::ubjson, "value")))
+        switch (m_object->m_type)
         {
-            return false;
+            case value_t::object:
+                JSON_THROW(invalid_iterator::create(209, "cannot use offsets with object iterators", *m_object));
+
+            case value_t::array:
+                return m_it.array_iterator - other.m_it.array_iterator;
+
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+                return m_it.primitive_iterator - other.m_it.primitive_iterator;
         }
+    }
 
-        switch (current)
+    /*!
+    @brief access to successor
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    reference operator[](difference_type n) const
+    {
+        JSON_ASSERT(m_object != nullptr);
+
+        switch (m_object->m_type)
         {
-            case 'U':
-            {
-                uint8_t len;
-                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
-            }
+            case value_t::object:
+                JSON_THROW(invalid_iterator::create(208, "cannot use operator[] for object iterators", *m_object));
 
-            case 'i':
-            {
-                int8_t len;
-                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
-            }
+            case value_t::array:
+                return *std::next(m_it.array_iterator, n);
 
-            case 'I':
-            {
-                int16_t len;
-                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
-            }
+            case value_t::null:
+                JSON_THROW(invalid_iterator::create(214, "cannot get value", *m_object));
 
-            case 'l':
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
             {
-                int32_t len;
-                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
-            }
+                if (JSON_HEDLEY_LIKELY(m_it.primitive_iterator.get_value() == -n))
+                {
+                    return *m_object;
+                }
 
-            case 'L':
-            {
-                int64_t len;
-                return get_number(input_format_t::ubjson, len) and get_string(input_format_t::ubjson, len, result);
+                JSON_THROW(invalid_iterator::create(214, "cannot get value", *m_object));
             }
-
-            default:
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "expected length type specification (U, i, I, l, L); last byte: 0x" + last_token, "string")));
         }
     }
 
     /*!
-    @param[out] result  determined size
-    @return whether size determination completed
+    @brief return the key of an object iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool get_ubjson_size_value(std::size_t& result)
+    const typename object_t::key_type& key() const
     {
-        switch (get_ignore_noop())
+        JSON_ASSERT(m_object != nullptr);
+
+        if (JSON_HEDLEY_LIKELY(m_object->is_object()))
         {
-            case 'U':
-            {
-                uint8_t number;
-                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
-                {
-                    return false;
-                }
-                result = static_cast<std::size_t>(number);
-                return true;
-            }
+            return m_it.object_iterator->first;
+        }
 
-            case 'i':
-            {
-                int8_t number;
-                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
-                {
-                    return false;
-                }
-                result = static_cast<std::size_t>(number);
-                return true;
-            }
+        JSON_THROW(invalid_iterator::create(207, "cannot use key() for non-object iterators", *m_object));
+    }
 
-            case 'I':
-            {
-                int16_t number;
-                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
-                {
-                    return false;
-                }
-                result = static_cast<std::size_t>(number);
-                return true;
-            }
+    /*!
+    @brief return the value of an iterator
+    @pre The iterator is initialized; i.e. `m_object != nullptr`.
+    */
+    reference value() const
+    {
+        return operator*();
+    }
+
+  JSON_PRIVATE_UNLESS_TESTED:
+    /// associated JSON instance
+    pointer m_object = nullptr;
+    /// the actual iterator of the associated instance
+    internal_iterator<typename std::remove_const<BasicJsonType>::type> m_it {};
+};
+} // namespace detail
+} // namespace nlohmann
+
+// #include <nlohmann/detail/iterators/iteration_proxy.hpp>
+
+// #include <nlohmann/detail/iterators/json_reverse_iterator.hpp>
+
+
+#include <cstddef> // ptrdiff_t
+#include <iterator> // reverse_iterator
+#include <utility> // declval
+
+namespace nlohmann
+{
+namespace detail
+{
+//////////////////////
+// reverse_iterator //
+//////////////////////
+
+/*!
+@brief a template for a reverse iterator class
+
+@tparam Base the base iterator type to reverse. Valid types are @ref
+iterator (to create @ref reverse_iterator) and @ref const_iterator (to
+create @ref const_reverse_iterator).
+
+@requirement The class satisfies the following concept requirements:
+-
+[BidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator):
+  The iterator that can be moved can be moved in both directions (i.e.
+  incremented and decremented).
+- [OutputIterator](https://en.cppreference.com/w/cpp/named_req/OutputIterator):
+  It is possible to write to the pointed-to element (only if @a Base is
+  @ref iterator).
+
+@since version 1.0.0
+*/
+template<typename Base>
+class json_reverse_iterator : public std::reverse_iterator<Base>
+{
+  public:
+    using difference_type = std::ptrdiff_t;
+    /// shortcut to the reverse iterator adapter
+    using base_iterator = std::reverse_iterator<Base>;
+    /// the reference type for the pointed-to element
+    using reference = typename Base::reference;
 
-            case 'l':
-            {
-                int32_t number;
-                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
-                {
-                    return false;
-                }
-                result = static_cast<std::size_t>(number);
-                return true;
-            }
+    /// create reverse iterator from iterator
+    explicit json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept
+        : base_iterator(it) {}
 
-            case 'L':
-            {
-                int64_t number;
-                if (JSON_UNLIKELY(not get_number(input_format_t::ubjson, number)))
-                {
-                    return false;
-                }
-                result = static_cast<std::size_t>(number);
-                return true;
-            }
+    /// create reverse iterator from base class
+    explicit json_reverse_iterator(const base_iterator& it) noexcept : base_iterator(it) {}
 
-            default:
-            {
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "expected length type specification (U, i, I, l, L) after '#'; last byte: 0x" + last_token, "size")));
-            }
-        }
+    /// post-increment (it++)
+    json_reverse_iterator const operator++(int) // NOLINT(readability-const-return-type)
+    {
+        return static_cast<json_reverse_iterator>(base_iterator::operator++(1));
     }
 
-    /*!
-    @brief determine the type and size for a container
-
-    In the optimized UBJSON format, a type and a size can be provided to allow
-    for a more compact representation.
+    /// pre-increment (++it)
+    json_reverse_iterator& operator++()
+    {
+        return static_cast<json_reverse_iterator&>(base_iterator::operator++());
+    }
 
-    @param[out] result  pair of the size and the type
+    /// post-decrement (it--)
+    json_reverse_iterator const operator--(int) // NOLINT(readability-const-return-type)
+    {
+        return static_cast<json_reverse_iterator>(base_iterator::operator--(1));
+    }
 
-    @return whether pair creation completed
-    */
-    bool get_ubjson_size_type(std::pair<std::size_t, int>& result)
+    /// pre-decrement (--it)
+    json_reverse_iterator& operator--()
     {
-        result.first = string_t::npos; // size
-        result.second = 0; // type
+        return static_cast<json_reverse_iterator&>(base_iterator::operator--());
+    }
 
-        get_ignore_noop();
+    /// add to iterator
+    json_reverse_iterator& operator+=(difference_type i)
+    {
+        return static_cast<json_reverse_iterator&>(base_iterator::operator+=(i));
+    }
 
-        if (current == '$')
-        {
-            result.second = get();  // must not ignore 'N', because 'N' maybe the type
-            if (JSON_UNLIKELY(not unexpect_eof(input_format_t::ubjson, "type")))
-            {
-                return false;
-            }
+    /// add to iterator
+    json_reverse_iterator operator+(difference_type i) const
+    {
+        return static_cast<json_reverse_iterator>(base_iterator::operator+(i));
+    }
 
-            get_ignore_noop();
-            if (JSON_UNLIKELY(current != '#'))
-            {
-                if (JSON_UNLIKELY(not unexpect_eof(input_format_t::ubjson, "value")))
-                {
-                    return false;
-                }
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::ubjson, "expected '#' after type information; last byte: 0x" + last_token, "size")));
-            }
+    /// subtract from iterator
+    json_reverse_iterator operator-(difference_type i) const
+    {
+        return static_cast<json_reverse_iterator>(base_iterator::operator-(i));
+    }
 
-            return get_ubjson_size_value(result.first);
-        }
-        else if (current == '#')
-        {
-            return get_ubjson_size_value(result.first);
-        }
-        return true;
+    /// return difference
+    difference_type operator-(const json_reverse_iterator& other) const
+    {
+        return base_iterator(*this) - base_iterator(other);
     }
 
-    /*!
-    @param prefix  the previously read or set type prefix
-    @return whether value creation completed
-    */
-    bool get_ubjson_value(const int prefix)
+    /// access to successor
+    reference operator[](difference_type n) const
     {
-        switch (prefix)
-        {
-            case std::char_traits<char>::eof():  // EOF
-                return unexpect_eof(input_format_t::ubjson, "value");
+        return *(this->operator+(n));
+    }
 
-            case 'T':  // true
-                return sax->boolean(true);
-            case 'F':  // false
-                return sax->boolean(false);
+    /// return the key of an object iterator
+    auto key() const -> decltype(std::declval<Base>().key())
+    {
+        auto it = --this->base();
+        return it.key();
+    }
 
-            case 'Z':  // null
-                return sax->null();
+    /// return the value of an iterator
+    reference value() const
+    {
+        auto it = --this->base();
+        return it.operator * ();
+    }
+};
+}  // namespace detail
+}  // namespace nlohmann
 
-            case 'U':
-            {
-                uint8_t number;
-                return get_number(input_format_t::ubjson, number) and sax->number_unsigned(number);
-            }
+// #include <nlohmann/detail/iterators/primitive_iterator.hpp>
 
-            case 'i':
-            {
-                int8_t number;
-                return get_number(input_format_t::ubjson, number) and sax->number_integer(number);
-            }
+// #include <nlohmann/detail/json_pointer.hpp>
 
-            case 'I':
-            {
-                int16_t number;
-                return get_number(input_format_t::ubjson, number) and sax->number_integer(number);
-            }
 
-            case 'l':
-            {
-                int32_t number;
-                return get_number(input_format_t::ubjson, number) and sax->number_integer(number);
-            }
+#include <algorithm> // all_of
+#include <cctype> // isdigit
+#include <limits> // max
+#include <numeric> // accumulate
+#include <string> // string
+#include <utility> // move
+#include <vector> // vector
 
-            case 'L':
-            {
-                int64_t number;
-                return get_number(input_format_t::ubjson, number) and sax->number_integer(number);
-            }
+// #include <nlohmann/detail/exceptions.hpp>
 
-            case 'd':
-            {
-                float number;
-                return get_number(input_format_t::ubjson, number) and sax->number_float(static_cast<number_float_t>(number), "");
-            }
+// #include <nlohmann/detail/macro_scope.hpp>
 
-            case 'D':
-            {
-                double number;
-                return get_number(input_format_t::ubjson, number) and sax->number_float(static_cast<number_float_t>(number), "");
-            }
+// #include <nlohmann/detail/string_escape.hpp>
 
-            case 'C':  // char
-            {
-                get();
-                if (JSON_UNLIKELY(not unexpect_eof(input_format_t::ubjson, "char")))
-                {
-                    return false;
-                }
-                if (JSON_UNLIKELY(current > 127))
-                {
-                    auto last_token = get_token_string();
-                    return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "byte after 'C' must be in range 0x00..0x7F; last byte: 0x" + last_token, "char")));
-                }
-                string_t s(1, static_cast<char>(current));
-                return sax->string(s);
-            }
+// #include <nlohmann/detail/value_t.hpp>
 
-            case 'S':  // string
-            {
-                string_t s;
-                return get_ubjson_string(s) and sax->string(s);
-            }
 
-            case '[':  // array
-                return get_ubjson_array();
+namespace nlohmann
+{
+template<typename BasicJsonType>
+class json_pointer
+{
+    // allow basic_json to access private members
+    NLOHMANN_BASIC_JSON_TPL_DECLARATION
+    friend class basic_json;
 
-            case '{':  // object
-                return get_ubjson_object();
+  public:
+    /*!
+    @brief create JSON pointer
 
-            default: // anything else
-            {
-                auto last_token = get_token_string();
-                return sax->parse_error(chars_read, last_token, parse_error::create(112, chars_read, exception_message(input_format_t::ubjson, "invalid byte: 0x" + last_token, "value")));
-            }
-        }
-    }
+    Create a JSON pointer according to the syntax described in
+    [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3).
 
-    /*!
-    @return whether array creation completed
-    */
-    bool get_ubjson_array()
-    {
-        std::pair<std::size_t, int> size_and_type;
-        if (JSON_UNLIKELY(not get_ubjson_size_type(size_and_type)))
-        {
-            return false;
-        }
+    @param[in] s  string representing the JSON pointer; if omitted, the empty
+                  string is assumed which references the whole JSON value
 
-        if (size_and_type.first != string_t::npos)
-        {
-            if (JSON_UNLIKELY(not sax->start_array(size_and_type.first)))
-            {
-                return false;
-            }
+    @throw parse_error.107 if the given JSON pointer @a s is nonempty and does
+                           not begin with a slash (`/`); see example below
 
-            if (size_and_type.second != 0)
-            {
-                if (size_and_type.second != 'N')
-                {
-                    for (std::size_t i = 0; i < size_and_type.first; ++i)
-                    {
-                        if (JSON_UNLIKELY(not get_ubjson_value(size_and_type.second)))
-                        {
-                            return false;
-                        }
-                    }
-                }
-            }
-            else
-            {
-                for (std::size_t i = 0; i < size_and_type.first; ++i)
-                {
-                    if (JSON_UNLIKELY(not parse_ubjson_internal()))
-                    {
-                        return false;
-                    }
-                }
-            }
-        }
-        else
-        {
-            if (JSON_UNLIKELY(not sax->start_array(std::size_t(-1))))
-            {
-                return false;
-            }
+    @throw parse_error.108 if a tilde (`~`) in the given JSON pointer @a s is
+    not followed by `0` (representing `~`) or `1` (representing `/`); see
+    example below
 
-            while (current != ']')
-            {
-                if (JSON_UNLIKELY(not parse_ubjson_internal(false)))
-                {
-                    return false;
-                }
-                get_ignore_noop();
-            }
-        }
+    @liveexample{The example shows the construction several valid JSON pointers
+    as well as the exceptional behavior.,json_pointer}
 
-        return sax->end_array();
-    }
+    @since version 2.0.0
+    */
+    explicit json_pointer(const std::string& s = "")
+        : reference_tokens(split(s))
+    {}
 
     /*!
-    @return whether object creation completed
+    @brief return a string representation of the JSON pointer
+
+    @invariant For each JSON pointer `ptr`, it holds:
+    @code {.cpp}
+    ptr == json_pointer(ptr.to_string());
+    @endcode
+
+    @return a string representation of the JSON pointer
+
+    @liveexample{The example shows the result of `to_string`.,json_pointer__to_string}
+
+    @since version 2.0.0
     */
-    bool get_ubjson_object()
+    std::string to_string() const
     {
-        std::pair<std::size_t, int> size_and_type;
-        if (JSON_UNLIKELY(not get_ubjson_size_type(size_and_type)))
+        return std::accumulate(reference_tokens.begin(), reference_tokens.end(),
+                               std::string{},
+                               [](const std::string & a, const std::string & b)
         {
-            return false;
-        }
+            return a + "/" + detail::escape(b);
+        });
+    }
 
-        string_t key;
-        if (size_and_type.first != string_t::npos)
-        {
-            if (JSON_UNLIKELY(not sax->start_object(size_and_type.first)))
-            {
-                return false;
-            }
+    /// @copydoc to_string()
+    operator std::string() const
+    {
+        return to_string();
+    }
 
-            if (size_and_type.second != 0)
-            {
-                for (std::size_t i = 0; i < size_and_type.first; ++i)
-                {
-                    if (JSON_UNLIKELY(not get_ubjson_string(key) or not sax->key(key)))
-                    {
-                        return false;
-                    }
-                    if (JSON_UNLIKELY(not get_ubjson_value(size_and_type.second)))
-                    {
-                        return false;
-                    }
-                    key.clear();
-                }
-            }
-            else
-            {
-                for (std::size_t i = 0; i < size_and_type.first; ++i)
-                {
-                    if (JSON_UNLIKELY(not get_ubjson_string(key) or not sax->key(key)))
-                    {
-                        return false;
-                    }
-                    if (JSON_UNLIKELY(not parse_ubjson_internal()))
-                    {
-                        return false;
-                    }
-                    key.clear();
-                }
-            }
-        }
-        else
-        {
-            if (JSON_UNLIKELY(not sax->start_object(std::size_t(-1))))
-            {
-                return false;
-            }
+    /*!
+    @brief append another JSON pointer at the end of this JSON pointer
 
-            while (current != '}')
-            {
-                if (JSON_UNLIKELY(not get_ubjson_string(key, false) or not sax->key(key)))
-                {
-                    return false;
-                }
-                if (JSON_UNLIKELY(not parse_ubjson_internal()))
-                {
-                    return false;
-                }
-                get_ignore_noop();
-                key.clear();
-            }
-        }
+    @param[in] ptr  JSON pointer to append
+    @return JSON pointer with @a ptr appended
 
-        return sax->end_object();
-    }
+    @liveexample{The example shows the usage of `operator/=`.,json_pointer__operator_add}
 
-    ///////////////////////
-    // Utility functions //
-    ///////////////////////
+    @complexity Linear in the length of @a ptr.
+
+    @sa see @ref operator/=(std::string) to append a reference token
+    @sa see @ref operator/=(std::size_t) to append an array index
+    @sa see @ref operator/(const json_pointer&, const json_pointer&) for a binary operator
+
+    @since version 3.6.0
+    */
+    json_pointer& operator/=(const json_pointer& ptr)
+    {
+        reference_tokens.insert(reference_tokens.end(),
+                                ptr.reference_tokens.begin(),
+                                ptr.reference_tokens.end());
+        return *this;
+    }
 
     /*!
-    @brief get next character from the input
+    @brief append an unescaped reference token at the end of this JSON pointer
 
-    This function provides the interface to the used input adapter. It does
-    not throw in case the input reached EOF, but returns a -'ve valued
-    `std::char_traits<char>::eof()` in that case.
+    @param[in] token  reference token to append
+    @return JSON pointer with @a token appended without escaping @a token
 
-    @return character read from the input
+    @liveexample{The example shows the usage of `operator/=`.,json_pointer__operator_add}
+
+    @complexity Amortized constant.
+
+    @sa see @ref operator/=(const json_pointer&) to append a JSON pointer
+    @sa see @ref operator/=(std::size_t) to append an array index
+    @sa see @ref operator/(const json_pointer&, std::size_t) for a binary operator
+
+    @since version 3.6.0
     */
-    int get()
+    json_pointer& operator/=(std::string token)
     {
-        ++chars_read;
-        return (current = ia->get_character());
+        push_back(std::move(token));
+        return *this;
     }
 
     /*!
-    @return character read from the input after ignoring all 'N' entries
+    @brief append an array index at the end of this JSON pointer
+
+    @param[in] array_idx  array index to append
+    @return JSON pointer with @a array_idx appended
+
+    @liveexample{The example shows the usage of `operator/=`.,json_pointer__operator_add}
+
+    @complexity Amortized constant.
+
+    @sa see @ref operator/=(const json_pointer&) to append a JSON pointer
+    @sa see @ref operator/=(std::string) to append a reference token
+    @sa see @ref operator/(const json_pointer&, std::string) for a binary operator
+
+    @since version 3.6.0
     */
-    int get_ignore_noop()
+    json_pointer& operator/=(std::size_t array_idx)
     {
-        do
-        {
-            get();
-        }
-        while (current == 'N');
-
-        return current;
+        return *this /= std::to_string(array_idx);
     }
 
-    /*
-    @brief read a number from the input
+    /*!
+    @brief create a new JSON pointer by appending the right JSON pointer at the end of the left JSON pointer
 
-    @tparam NumberType the type of the number
-    @param[in] format   the current format (for diagnostics)
-    @param[out] result  number of type @a NumberType
+    @param[in] lhs  JSON pointer
+    @param[in] rhs  JSON pointer
+    @return a new JSON pointer with @a rhs appended to @a lhs
 
-    @return whether conversion completed
+    @liveexample{The example shows the usage of `operator/`.,json_pointer__operator_add_binary}
 
-    @note This function needs to respect the system's endianess, because
-          bytes in CBOR, MessagePack, and UBJSON are stored in network order
-          (big endian) and therefore need reordering on little endian systems.
+    @complexity Linear in the length of @a lhs and @a rhs.
+
+    @sa see @ref operator/=(const json_pointer&) to append a JSON pointer
+
+    @since version 3.6.0
     */
-    template<typename NumberType, bool InputIsLittleEndian = false>
-    bool get_number(const input_format_t format, NumberType& result)
+    friend json_pointer operator/(const json_pointer& lhs,
+                                  const json_pointer& rhs)
     {
-        // step 1: read input into array with system's byte order
-        std::array<uint8_t, sizeof(NumberType)> vec;
-        for (std::size_t i = 0; i < sizeof(NumberType); ++i)
-        {
-            get();
-            if (JSON_UNLIKELY(not unexpect_eof(format, "number")))
-            {
-                return false;
-            }
+        return json_pointer(lhs) /= rhs;
+    }
 
-            // reverse byte order prior to conversion if necessary
-            if (is_little_endian && !InputIsLittleEndian)
-            {
-                vec[sizeof(NumberType) - i - 1] = static_cast<uint8_t>(current);
-            }
-            else
-            {
-                vec[i] = static_cast<uint8_t>(current); // LCOV_EXCL_LINE
-            }
-        }
+    /*!
+    @brief create a new JSON pointer by appending the unescaped token at the end of the JSON pointer
 
-        // step 2: convert array into number of type T and return
-        std::memcpy(&result, vec.data(), sizeof(NumberType));
-        return true;
+    @param[in] ptr  JSON pointer
+    @param[in] token  reference token
+    @return a new JSON pointer with unescaped @a token appended to @a ptr
+
+    @liveexample{The example shows the usage of `operator/`.,json_pointer__operator_add_binary}
+
+    @complexity Linear in the length of @a ptr.
+
+    @sa see @ref operator/=(std::string) to append a reference token
+
+    @since version 3.6.0
+    */
+    friend json_pointer operator/(const json_pointer& ptr, std::string token) // NOLINT(performance-unnecessary-value-param)
+    {
+        return json_pointer(ptr) /= std::move(token);
     }
 
     /*!
-    @brief create a string by reading characters from the input
+    @brief create a new JSON pointer by appending the array-index-token at the end of the JSON pointer
 
-    @tparam NumberType the type of the number
-    @param[in] format the current format (for diagnostics)
-    @param[in] len number of characters to read
-    @param[out] result string created by reading @a len bytes
+    @param[in] ptr  JSON pointer
+    @param[in] array_idx  array index
+    @return a new JSON pointer with @a array_idx appended to @a ptr
 
-    @return whether string creation completed
+    @liveexample{The example shows the usage of `operator/`.,json_pointer__operator_add_binary}
 
-    @note We can not reserve @a len bytes for the result, because @a len
-          may be too large. Usually, @ref unexpect_eof() detects the end of
-          the input before we run out of string memory.
+    @complexity Linear in the length of @a ptr.
+
+    @sa see @ref operator/=(std::size_t) to append an array index
+
+    @since version 3.6.0
     */
-    template<typename NumberType>
-    bool get_string(const input_format_t format,
-                    const NumberType len,
-                    string_t& result)
+    friend json_pointer operator/(const json_pointer& ptr, std::size_t array_idx)
     {
-        bool success = true;
-        std::generate_n(std::back_inserter(result), len, [this, &success, &format]()
-        {
-            get();
-            if (JSON_UNLIKELY(not unexpect_eof(format, "string")))
-            {
-                success = false;
-            }
-            return static_cast<char>(current);
-        });
-        return success;
+        return json_pointer(ptr) /= array_idx;
     }
 
     /*!
-    @param[in] format   the current format (for diagnostics)
-    @param[in] context  further context information (for diagnostics)
-    @return whether the last read character is not EOF
+    @brief returns the parent of this JSON pointer
+
+    @return parent of this JSON pointer; in case this JSON pointer is the root,
+            the root itself is returned
+
+    @complexity Linear in the length of the JSON pointer.
+
+    @liveexample{The example shows the result of `parent_pointer` for different
+    JSON Pointers.,json_pointer__parent_pointer}
+
+    @since version 3.6.0
     */
-    bool unexpect_eof(const input_format_t format, const char* context) const
+    json_pointer parent_pointer() const
     {
-        if (JSON_UNLIKELY(current == std::char_traits<char>::eof()))
+        if (empty())
         {
-            return sax->parse_error(chars_read, "<end of file>",
-                                    parse_error::create(110, chars_read, exception_message(format, "unexpected end of input", context)));
+            return *this;
         }
-        return true;
+
+        json_pointer res = *this;
+        res.pop_back();
+        return res;
     }
 
     /*!
-    @return a string representation of the last read byte
+    @brief remove last reference token
+
+    @pre not `empty()`
+
+    @liveexample{The example shows the usage of `pop_back`.,json_pointer__pop_back}
+
+    @complexity Constant.
+
+    @throw out_of_range.405 if JSON pointer has no parent
+
+    @since version 3.6.0
     */
-    std::string get_token_string() const
+    void pop_back()
     {
-        char cr[3];
-        (std::snprintf)(cr, 3, "%.2hhX", static_cast<unsigned char>(current));
-        return std::string{cr};
+        if (JSON_HEDLEY_UNLIKELY(empty()))
+        {
+            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent", BasicJsonType()));
+        }
+
+        reference_tokens.pop_back();
     }
 
     /*!
-    @param[in] format   the current format
-    @param[in] detail   a detailed error message
-    @param[in] context  further contect information
-    @return a message string to use in the parse_error exceptions
-    */
-    std::string exception_message(const input_format_t format,
-                                  const std::string& detail,
-                                  const std::string& context) const
-    {
-        std::string error_msg = "syntax error while parsing ";
+    @brief return last reference token
 
-        switch (format)
-        {
-            case input_format_t::cbor:
-                error_msg += "CBOR";
-                break;
+    @pre not `empty()`
+    @return last reference token
 
-            case input_format_t::msgpack:
-                error_msg += "MessagePack";
-                break;
+    @liveexample{The example shows the usage of `back`.,json_pointer__back}
 
-            case input_format_t::ubjson:
-                error_msg += "UBJSON";
-                break;
+    @complexity Constant.
 
-            case input_format_t::bson:
-                error_msg += "BSON";
-                break;
+    @throw out_of_range.405 if JSON pointer has no parent
 
-            // LCOV_EXCL_START
-            default:
-                assert(false);
-                // LCOV_EXCL_STOP
+    @since version 3.6.0
+    */
+    const std::string& back() const
+    {
+        if (JSON_HEDLEY_UNLIKELY(empty()))
+        {
+            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent", BasicJsonType()));
         }
 
-        return error_msg + " " + context + ": " + detail;
+        return reference_tokens.back();
     }
 
-  private:
-    /// input adapter
-    input_adapter_t ia = nullptr;
-
-    /// the current character
-    int current = std::char_traits<char>::eof();
-
-    /// the number of characters read
-    std::size_t chars_read = 0;
-
-    /// whether we can assume little endianess
-    const bool is_little_endian = little_endianess();
+    /*!
+    @brief append an unescaped token at the end of the reference pointer
 
-    /// the SAX parser
-    json_sax_t* sax = nullptr;
-};
-}  // namespace detail
-}  // namespace nlohmann
+    @param[in] token  token to add
 
-// #include <nlohmann/detail/output/binary_writer.hpp>
+    @complexity Amortized constant.
 
+    @liveexample{The example shows the result of `push_back` for different
+    JSON Pointers.,json_pointer__push_back}
 
-#include <algorithm> // reverse
-#include <array> // array
-#include <cstdint> // uint8_t, uint16_t, uint32_t, uint64_t
-#include <cstring> // memcpy
-#include <limits> // numeric_limits
+    @since version 3.6.0
+    */
+    void push_back(const std::string& token)
+    {
+        reference_tokens.push_back(token);
+    }
 
-// #include <nlohmann/detail/input/binary_reader.hpp>
+    /// @copydoc push_back(const std::string&)
+    void push_back(std::string&& token)
+    {
+        reference_tokens.push_back(std::move(token));
+    }
 
-// #include <nlohmann/detail/output/output_adapters.hpp>
+    /*!
+    @brief return whether pointer points to the root document
 
+    @return true iff the JSON pointer points to the root document
 
-namespace nlohmann
-{
-namespace detail
-{
-///////////////////
-// binary writer //
-///////////////////
+    @complexity Constant.
 
-/*!
-@brief serialization to CBOR and MessagePack values
-*/
-template<typename BasicJsonType, typename CharType>
-class binary_writer
-{
-    using string_t = typename BasicJsonType::string_t;
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
 
-  public:
-    /*!
-    @brief create a binary writer
+    @liveexample{The example shows the result of `empty` for different JSON
+    Pointers.,json_pointer__empty}
 
-    @param[in] adapter  output adapter to write to
+    @since version 3.6.0
     */
-    explicit binary_writer(output_adapter_t<CharType> adapter) : oa(adapter)
+    bool empty() const noexcept
     {
-        assert(oa);
+        return reference_tokens.empty();
     }
 
+  private:
     /*!
-    @param[in] j  JSON value to serialize
-    @pre       j.type() == value_t::object
+    @param[in] s  reference token to be converted into an array index
+
+    @return integer representation of @a s
+
+    @throw parse_error.106  if an array index begins with '0'
+    @throw parse_error.109  if an array index begins not with a digit
+    @throw out_of_range.404 if string @a s could not be converted to an integer
+    @throw out_of_range.410 if an array index exceeds size_type
     */
-    void write_bson(const BasicJsonType& j)
+    static typename BasicJsonType::size_type array_index(const std::string& s)
     {
-        switch (j.type())
+        using size_type = typename BasicJsonType::size_type;
+
+        // error condition (cf. RFC 6901, Sect. 4)
+        if (JSON_HEDLEY_UNLIKELY(s.size() > 1 && s[0] == '0'))
         {
-            case value_t::object:
-            {
-                write_bson_object(*j.m_value.object);
-                break;
-            }
+            JSON_THROW(detail::parse_error::create(106, 0, "array index '" + s + "' must not begin with '0'", BasicJsonType()));
+        }
 
-            default:
-            {
-                JSON_THROW(type_error::create(317, "to serialize to BSON, top-level type must be object, but is " + std::string(j.type_name())));
-            }
+        // error condition (cf. RFC 6901, Sect. 4)
+        if (JSON_HEDLEY_UNLIKELY(s.size() > 1 && !(s[0] >= '1' && s[0] <= '9')))
+        {
+            JSON_THROW(detail::parse_error::create(109, 0, "array index '" + s + "' is not a number", BasicJsonType()));
+        }
+
+        std::size_t processed_chars = 0;
+        unsigned long long res = 0;  // NOLINT(runtime/int)
+        JSON_TRY
+        {
+            res = std::stoull(s, &processed_chars);
+        }
+        JSON_CATCH(std::out_of_range&)
+        {
+            JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + s + "'", BasicJsonType()));
+        }
+
+        // check if the string was completely read
+        if (JSON_HEDLEY_UNLIKELY(processed_chars != s.size()))
+        {
+            JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + s + "'", BasicJsonType()));
+        }
+
+        // only triggered on special platforms (like 32bit), see also
+        // https://github.com/nlohmann/json/pull/2203
+        if (res >= static_cast<unsigned long long>((std::numeric_limits<size_type>::max)()))  // NOLINT(runtime/int)
+        {
+            JSON_THROW(detail::out_of_range::create(410, "array index " + s + " exceeds size_type", BasicJsonType())); // LCOV_EXCL_LINE
         }
+
+        return static_cast<size_type>(res);
     }
 
-    /*!
-    @param[in] j  JSON value to serialize
-    */
-    void write_cbor(const BasicJsonType& j)
+  JSON_PRIVATE_UNLESS_TESTED:
+    json_pointer top() const
     {
-        switch (j.type())
+        if (JSON_HEDLEY_UNLIKELY(empty()))
         {
-            case value_t::null:
-            {
-                oa->write_character(to_char_type(0xF6));
-                break;
-            }
+            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent", BasicJsonType()));
+        }
 
-            case value_t::boolean:
-            {
-                oa->write_character(j.m_value.boolean
-                                    ? to_char_type(0xF5)
-                                    : to_char_type(0xF4));
-                break;
-            }
+        json_pointer result = *this;
+        result.reference_tokens = {reference_tokens[0]};
+        return result;
+    }
 
-            case value_t::number_integer:
+  private:
+    /*!
+    @brief create and return a reference to the pointed to value
+
+    @complexity Linear in the number of reference tokens.
+
+    @throw parse_error.109 if array index is not a number
+    @throw type_error.313 if value cannot be unflattened
+    */
+    BasicJsonType& get_and_create(BasicJsonType& j) const
+    {
+        auto* result = &j;
+
+        // in case no reference tokens exist, return a reference to the JSON value
+        // j which will be overwritten by a primitive value
+        for (const auto& reference_token : reference_tokens)
+        {
+            switch (result->type())
             {
-                if (j.m_value.number_integer >= 0)
-                {
-                    // CBOR does not differentiate between positive signed
-                    // integers and unsigned integers. Therefore, we used the
-                    // code from the value_t::number_unsigned case here.
-                    if (j.m_value.number_integer <= 0x17)
-                    {
-                        write_number(static_cast<uint8_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_integer <= (std::numeric_limits<uint8_t>::max)())
-                    {
-                        oa->write_character(to_char_type(0x18));
-                        write_number(static_cast<uint8_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_integer <= (std::numeric_limits<uint16_t>::max)())
-                    {
-                        oa->write_character(to_char_type(0x19));
-                        write_number(static_cast<uint16_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_integer <= (std::numeric_limits<uint32_t>::max)())
-                    {
-                        oa->write_character(to_char_type(0x1A));
-                        write_number(static_cast<uint32_t>(j.m_value.number_integer));
-                    }
-                    else
-                    {
-                        oa->write_character(to_char_type(0x1B));
-                        write_number(static_cast<uint64_t>(j.m_value.number_integer));
-                    }
-                }
-                else
+                case detail::value_t::null:
                 {
-                    // The conversions below encode the sign in the first
-                    // byte, and the value is converted to a positive number.
-                    const auto positive_number = -1 - j.m_value.number_integer;
-                    if (j.m_value.number_integer >= -24)
-                    {
-                        write_number(static_cast<uint8_t>(0x20 + positive_number));
-                    }
-                    else if (positive_number <= (std::numeric_limits<uint8_t>::max)())
-                    {
-                        oa->write_character(to_char_type(0x38));
-                        write_number(static_cast<uint8_t>(positive_number));
-                    }
-                    else if (positive_number <= (std::numeric_limits<uint16_t>::max)())
-                    {
-                        oa->write_character(to_char_type(0x39));
-                        write_number(static_cast<uint16_t>(positive_number));
-                    }
-                    else if (positive_number <= (std::numeric_limits<uint32_t>::max)())
+                    if (reference_token == "0")
                     {
-                        oa->write_character(to_char_type(0x3A));
-                        write_number(static_cast<uint32_t>(positive_number));
+                        // start a new array if reference token is 0
+                        result = &result->operator[](0);
                     }
                     else
                     {
-                        oa->write_character(to_char_type(0x3B));
-                        write_number(static_cast<uint64_t>(positive_number));
+                        // start a new object otherwise
+                        result = &result->operator[](reference_token);
                     }
+                    break;
                 }
-                break;
-            }
-
-            case value_t::number_unsigned:
-            {
-                if (j.m_value.number_unsigned <= 0x17)
-                {
-                    write_number(static_cast<uint8_t>(j.m_value.number_unsigned));
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x18));
-                    write_number(static_cast<uint8_t>(j.m_value.number_unsigned));
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x19));
-                    write_number(static_cast<uint16_t>(j.m_value.number_unsigned));
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x1A));
-                    write_number(static_cast<uint32_t>(j.m_value.number_unsigned));
-                }
-                else
-                {
-                    oa->write_character(to_char_type(0x1B));
-                    write_number(static_cast<uint64_t>(j.m_value.number_unsigned));
-                }
-                break;
-            }
-
-            case value_t::number_float:
-            {
-                oa->write_character(get_cbor_float_prefix(j.m_value.number_float));
-                write_number(j.m_value.number_float);
-                break;
-            }
-
-            case value_t::string:
-            {
-                // step 1: write control byte and the string length
-                const auto N = j.m_value.string->size();
-                if (N <= 0x17)
-                {
-                    write_number(static_cast<uint8_t>(0x60 + N));
-                }
-                else if (N <= (std::numeric_limits<uint8_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x78));
-                    write_number(static_cast<uint8_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint16_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x79));
-                    write_number(static_cast<uint16_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint32_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x7A));
-                    write_number(static_cast<uint32_t>(N));
-                }
-                // LCOV_EXCL_START
-                else if (N <= (std::numeric_limits<uint64_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x7B));
-                    write_number(static_cast<uint64_t>(N));
-                }
-                // LCOV_EXCL_STOP
-
-                // step 2: write the string
-                oa->write_characters(
-                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
-                    j.m_value.string->size());
-                break;
-            }
-
-            case value_t::array:
-            {
-                // step 1: write control byte and the array size
-                const auto N = j.m_value.array->size();
-                if (N <= 0x17)
-                {
-                    write_number(static_cast<uint8_t>(0x80 + N));
-                }
-                else if (N <= (std::numeric_limits<uint8_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x98));
-                    write_number(static_cast<uint8_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint16_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x99));
-                    write_number(static_cast<uint16_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint32_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x9A));
-                    write_number(static_cast<uint32_t>(N));
-                }
-                // LCOV_EXCL_START
-                else if (N <= (std::numeric_limits<uint64_t>::max)())
-                {
-                    oa->write_character(to_char_type(0x9B));
-                    write_number(static_cast<uint64_t>(N));
-                }
-                // LCOV_EXCL_STOP
-
-                // step 2: write each element
-                for (const auto& el : *j.m_value.array)
-                {
-                    write_cbor(el);
-                }
-                break;
-            }
 
-            case value_t::object:
-            {
-                // step 1: write control byte and the object size
-                const auto N = j.m_value.object->size();
-                if (N <= 0x17)
-                {
-                    write_number(static_cast<uint8_t>(0xA0 + N));
-                }
-                else if (N <= (std::numeric_limits<uint8_t>::max)())
-                {
-                    oa->write_character(to_char_type(0xB8));
-                    write_number(static_cast<uint8_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint16_t>::max)())
-                {
-                    oa->write_character(to_char_type(0xB9));
-                    write_number(static_cast<uint16_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint32_t>::max)())
-                {
-                    oa->write_character(to_char_type(0xBA));
-                    write_number(static_cast<uint32_t>(N));
-                }
-                // LCOV_EXCL_START
-                else if (N <= (std::numeric_limits<uint64_t>::max)())
+                case detail::value_t::object:
                 {
-                    oa->write_character(to_char_type(0xBB));
-                    write_number(static_cast<uint64_t>(N));
+                    // create an entry in the object
+                    result = &result->operator[](reference_token);
+                    break;
                 }
-                // LCOV_EXCL_STOP
 
-                // step 2: write each element
-                for (const auto& el : *j.m_value.object)
+                case detail::value_t::array:
                 {
-                    write_cbor(el.first);
-                    write_cbor(el.second);
+                    // create an entry in the array
+                    result = &result->operator[](array_index(reference_token));
+                    break;
                 }
-                break;
-            }
 
-            default:
-                break;
+                /*
+                The following code is only reached if there exists a reference
+                token _and_ the current value is primitive. In this case, we have
+                an error situation, because primitive values may only occur as
+                single value; that is, with an empty list of reference tokens.
+                */
+                case detail::value_t::string:
+                case detail::value_t::boolean:
+                case detail::value_t::number_integer:
+                case detail::value_t::number_unsigned:
+                case detail::value_t::number_float:
+                case detail::value_t::binary:
+                case detail::value_t::discarded:
+                default:
+                    JSON_THROW(detail::type_error::create(313, "invalid value to unflatten", j));
+            }
         }
+
+        return *result;
     }
 
     /*!
-    @param[in] j  JSON value to serialize
+    @brief return a reference to the pointed to value
+
+    @note This version does not throw if a value is not present, but tries to
+          create nested values instead. For instance, calling this function
+          with pointer `"/this/that"` on a null value is equivalent to calling
+          `operator[]("this").operator[]("that")` on that value, effectively
+          changing the null value to an object.
+
+    @param[in] ptr  a JSON value
+
+    @return reference to the JSON value pointed to by the JSON pointer
+
+    @complexity Linear in the length of the JSON pointer.
+
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.404  if the JSON pointer can not be resolved
     */
-    void write_msgpack(const BasicJsonType& j)
+    BasicJsonType& get_unchecked(BasicJsonType* ptr) const
     {
-        switch (j.type())
+        for (const auto& reference_token : reference_tokens)
         {
-            case value_t::null: // nil
+            // convert null values to arrays or objects before continuing
+            if (ptr->is_null())
             {
-                oa->write_character(to_char_type(0xC0));
-                break;
-            }
+                // check if reference token is a number
+                const bool nums =
+                    std::all_of(reference_token.begin(), reference_token.end(),
+                                [](const unsigned char x)
+                {
+                    return std::isdigit(x);
+                });
 
-            case value_t::boolean: // true and false
-            {
-                oa->write_character(j.m_value.boolean
-                                    ? to_char_type(0xC3)
-                                    : to_char_type(0xC2));
-                break;
+                // change value to array for numbers or "-" or to object otherwise
+                *ptr = (nums || reference_token == "-")
+                       ? detail::value_t::array
+                       : detail::value_t::object;
             }
 
-            case value_t::number_integer:
+            switch (ptr->type())
             {
-                if (j.m_value.number_integer >= 0)
+                case detail::value_t::object:
                 {
-                    // MessagePack does not differentiate between positive
-                    // signed integers and unsigned integers. Therefore, we used
-                    // the code from the value_t::number_unsigned case here.
-                    if (j.m_value.number_unsigned < 128)
-                    {
-                        // positive fixnum
-                        write_number(static_cast<uint8_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
-                    {
-                        // uint 8
-                        oa->write_character(to_char_type(0xCC));
-                        write_number(static_cast<uint8_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
-                    {
-                        // uint 16
-                        oa->write_character(to_char_type(0xCD));
-                        write_number(static_cast<uint16_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
-                    {
-                        // uint 32
-                        oa->write_character(to_char_type(0xCE));
-                        write_number(static_cast<uint32_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)())
-                    {
-                        // uint 64
-                        oa->write_character(to_char_type(0xCF));
-                        write_number(static_cast<uint64_t>(j.m_value.number_integer));
-                    }
+                    // use unchecked object access
+                    ptr = &ptr->operator[](reference_token);
+                    break;
                 }
-                else
+
+                case detail::value_t::array:
                 {
-                    if (j.m_value.number_integer >= -32)
-                    {
-                        // negative fixnum
-                        write_number(static_cast<int8_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_integer >= (std::numeric_limits<int8_t>::min)() and
-                             j.m_value.number_integer <= (std::numeric_limits<int8_t>::max)())
-                    {
-                        // int 8
-                        oa->write_character(to_char_type(0xD0));
-                        write_number(static_cast<int8_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_integer >= (std::numeric_limits<int16_t>::min)() and
-                             j.m_value.number_integer <= (std::numeric_limits<int16_t>::max)())
-                    {
-                        // int 16
-                        oa->write_character(to_char_type(0xD1));
-                        write_number(static_cast<int16_t>(j.m_value.number_integer));
-                    }
-                    else if (j.m_value.number_integer >= (std::numeric_limits<int32_t>::min)() and
-                             j.m_value.number_integer <= (std::numeric_limits<int32_t>::max)())
+                    if (reference_token == "-")
                     {
-                        // int 32
-                        oa->write_character(to_char_type(0xD2));
-                        write_number(static_cast<int32_t>(j.m_value.number_integer));
+                        // explicitly treat "-" as index beyond the end
+                        ptr = &ptr->operator[](ptr->m_value.array->size());
                     }
-                    else if (j.m_value.number_integer >= (std::numeric_limits<int64_t>::min)() and
-                             j.m_value.number_integer <= (std::numeric_limits<int64_t>::max)())
+                    else
                     {
-                        // int 64
-                        oa->write_character(to_char_type(0xD3));
-                        write_number(static_cast<int64_t>(j.m_value.number_integer));
+                        // convert array index to number; unchecked access
+                        ptr = &ptr->operator[](array_index(reference_token));
                     }
+                    break;
                 }
-                break;
-            }
 
-            case value_t::number_unsigned:
-            {
-                if (j.m_value.number_unsigned < 128)
-                {
-                    // positive fixnum
-                    write_number(static_cast<uint8_t>(j.m_value.number_integer));
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
-                {
-                    // uint 8
-                    oa->write_character(to_char_type(0xCC));
-                    write_number(static_cast<uint8_t>(j.m_value.number_integer));
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint16_t>::max)())
-                {
-                    // uint 16
-                    oa->write_character(to_char_type(0xCD));
-                    write_number(static_cast<uint16_t>(j.m_value.number_integer));
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint32_t>::max)())
-                {
-                    // uint 32
-                    oa->write_character(to_char_type(0xCE));
-                    write_number(static_cast<uint32_t>(j.m_value.number_integer));
-                }
-                else if (j.m_value.number_unsigned <= (std::numeric_limits<uint64_t>::max)())
-                {
-                    // uint 64
-                    oa->write_character(to_char_type(0xCF));
-                    write_number(static_cast<uint64_t>(j.m_value.number_integer));
-                }
-                break;
+                case detail::value_t::null:
+                case detail::value_t::string:
+                case detail::value_t::boolean:
+                case detail::value_t::number_integer:
+                case detail::value_t::number_unsigned:
+                case detail::value_t::number_float:
+                case detail::value_t::binary:
+                case detail::value_t::discarded:
+                default:
+                    JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'", *ptr));
             }
+        }
 
-            case value_t::number_float:
-            {
-                oa->write_character(get_msgpack_float_prefix(j.m_value.number_float));
-                write_number(j.m_value.number_float);
-                break;
-            }
+        return *ptr;
+    }
 
-            case value_t::string:
+    /*!
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.402  if the array index '-' is used
+    @throw out_of_range.404  if the JSON pointer can not be resolved
+    */
+    BasicJsonType& get_checked(BasicJsonType* ptr) const
+    {
+        for (const auto& reference_token : reference_tokens)
+        {
+            switch (ptr->type())
             {
-                // step 1: write control byte and the string length
-                const auto N = j.m_value.string->size();
-                if (N <= 31)
-                {
-                    // fixstr
-                    write_number(static_cast<uint8_t>(0xA0 | N));
-                }
-                else if (N <= (std::numeric_limits<uint8_t>::max)())
-                {
-                    // str 8
-                    oa->write_character(to_char_type(0xD9));
-                    write_number(static_cast<uint8_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint16_t>::max)())
+                case detail::value_t::object:
                 {
-                    // str 16
-                    oa->write_character(to_char_type(0xDA));
-                    write_number(static_cast<uint16_t>(N));
+                    // note: at performs range check
+                    ptr = &ptr->at(reference_token);
+                    break;
                 }
-                else if (N <= (std::numeric_limits<uint32_t>::max)())
+
+                case detail::value_t::array:
                 {
-                    // str 32
-                    oa->write_character(to_char_type(0xDB));
-                    write_number(static_cast<uint32_t>(N));
+                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    {
+                        // "-" always fails the range check
+                        JSON_THROW(detail::out_of_range::create(402,
+                                                                "array index '-' (" + std::to_string(ptr->m_value.array->size()) +
+                                                                ") is out of range", *ptr));
+                    }
+
+                    // note: at performs range check
+                    ptr = &ptr->at(array_index(reference_token));
+                    break;
                 }
 
-                // step 2: write the string
-                oa->write_characters(
-                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
-                    j.m_value.string->size());
-                break;
+                case detail::value_t::null:
+                case detail::value_t::string:
+                case detail::value_t::boolean:
+                case detail::value_t::number_integer:
+                case detail::value_t::number_unsigned:
+                case detail::value_t::number_float:
+                case detail::value_t::binary:
+                case detail::value_t::discarded:
+                default:
+                    JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'", *ptr));
             }
+        }
 
-            case value_t::array:
-            {
-                // step 1: write control byte and the array size
-                const auto N = j.m_value.array->size();
-                if (N <= 15)
-                {
-                    // fixarray
-                    write_number(static_cast<uint8_t>(0x90 | N));
-                }
-                else if (N <= (std::numeric_limits<uint16_t>::max)())
-                {
-                    // array 16
-                    oa->write_character(to_char_type(0xDC));
-                    write_number(static_cast<uint16_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint32_t>::max)())
-                {
-                    // array 32
-                    oa->write_character(to_char_type(0xDD));
-                    write_number(static_cast<uint32_t>(N));
-                }
+        return *ptr;
+    }
 
-                // step 2: write each element
-                for (const auto& el : *j.m_value.array)
-                {
-                    write_msgpack(el);
-                }
-                break;
-            }
+    /*!
+    @brief return a const reference to the pointed to value
 
-            case value_t::object:
+    @param[in] ptr  a JSON value
+
+    @return const reference to the JSON value pointed to by the JSON
+    pointer
+
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.402  if the array index '-' is used
+    @throw out_of_range.404  if the JSON pointer can not be resolved
+    */
+    const BasicJsonType& get_unchecked(const BasicJsonType* ptr) const
+    {
+        for (const auto& reference_token : reference_tokens)
+        {
+            switch (ptr->type())
             {
-                // step 1: write control byte and the object size
-                const auto N = j.m_value.object->size();
-                if (N <= 15)
-                {
-                    // fixmap
-                    write_number(static_cast<uint8_t>(0x80 | (N & 0xF)));
-                }
-                else if (N <= (std::numeric_limits<uint16_t>::max)())
-                {
-                    // map 16
-                    oa->write_character(to_char_type(0xDE));
-                    write_number(static_cast<uint16_t>(N));
-                }
-                else if (N <= (std::numeric_limits<uint32_t>::max)())
-                {
-                    // map 32
-                    oa->write_character(to_char_type(0xDF));
-                    write_number(static_cast<uint32_t>(N));
+                case detail::value_t::object:
+                {
+                    // use unchecked object access
+                    ptr = &ptr->operator[](reference_token);
+                    break;
                 }
 
-                // step 2: write each element
-                for (const auto& el : *j.m_value.object)
+                case detail::value_t::array:
                 {
-                    write_msgpack(el.first);
-                    write_msgpack(el.second);
+                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    {
+                        // "-" cannot be used for const access
+                        JSON_THROW(detail::out_of_range::create(402, "array index '-' (" + std::to_string(ptr->m_value.array->size()) + ") is out of range", *ptr));
+                    }
+
+                    // use unchecked array access
+                    ptr = &ptr->operator[](array_index(reference_token));
+                    break;
                 }
-                break;
-            }
 
-            default:
-                break;
+                case detail::value_t::null:
+                case detail::value_t::string:
+                case detail::value_t::boolean:
+                case detail::value_t::number_integer:
+                case detail::value_t::number_unsigned:
+                case detail::value_t::number_float:
+                case detail::value_t::binary:
+                case detail::value_t::discarded:
+                default:
+                    JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'", *ptr));
+            }
         }
+
+        return *ptr;
     }
 
     /*!
-    @param[in] j  JSON value to serialize
-    @param[in] use_count   whether to use '#' prefixes (optimized format)
-    @param[in] use_type    whether to use '$' prefixes (optimized format)
-    @param[in] add_prefix  whether prefixes need to be used for this value
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    @throw out_of_range.402  if the array index '-' is used
+    @throw out_of_range.404  if the JSON pointer can not be resolved
     */
-    void write_ubjson(const BasicJsonType& j, const bool use_count,
-                      const bool use_type, const bool add_prefix = true)
+    const BasicJsonType& get_checked(const BasicJsonType* ptr) const
     {
-        switch (j.type())
+        for (const auto& reference_token : reference_tokens)
         {
-            case value_t::null:
+            switch (ptr->type())
             {
-                if (add_prefix)
+                case detail::value_t::object:
                 {
-                    oa->write_character(to_char_type('Z'));
+                    // note: at performs range check
+                    ptr = &ptr->at(reference_token);
+                    break;
                 }
-                break;
-            }
 
-            case value_t::boolean:
-            {
-                if (add_prefix)
+                case detail::value_t::array:
                 {
-                    oa->write_character(j.m_value.boolean
-                                        ? to_char_type('T')
-                                        : to_char_type('F'));
-                }
-                break;
-            }
+                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    {
+                        // "-" always fails the range check
+                        JSON_THROW(detail::out_of_range::create(402,
+                                                                "array index '-' (" + std::to_string(ptr->m_value.array->size()) +
+                                                                ") is out of range", *ptr));
+                    }
 
-            case value_t::number_integer:
-            {
-                write_number_with_ubjson_prefix(j.m_value.number_integer, add_prefix);
-                break;
-            }
+                    // note: at performs range check
+                    ptr = &ptr->at(array_index(reference_token));
+                    break;
+                }
 
-            case value_t::number_unsigned:
-            {
-                write_number_with_ubjson_prefix(j.m_value.number_unsigned, add_prefix);
-                break;
+                case detail::value_t::null:
+                case detail::value_t::string:
+                case detail::value_t::boolean:
+                case detail::value_t::number_integer:
+                case detail::value_t::number_unsigned:
+                case detail::value_t::number_float:
+                case detail::value_t::binary:
+                case detail::value_t::discarded:
+                default:
+                    JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'", *ptr));
             }
+        }
 
-            case value_t::number_float:
-            {
-                write_number_with_ubjson_prefix(j.m_value.number_float, add_prefix);
-                break;
-            }
+        return *ptr;
+    }
 
-            case value_t::string:
+    /*!
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+    */
+    bool contains(const BasicJsonType* ptr) const
+    {
+        for (const auto& reference_token : reference_tokens)
+        {
+            switch (ptr->type())
             {
-                if (add_prefix)
+                case detail::value_t::object:
                 {
-                    oa->write_character(to_char_type('S'));
-                }
-                write_number_with_ubjson_prefix(j.m_value.string->size(), true);
-                oa->write_characters(
-                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
-                    j.m_value.string->size());
-                break;
-            }
+                    if (!ptr->contains(reference_token))
+                    {
+                        // we did not find the key in the object
+                        return false;
+                    }
 
-            case value_t::array:
-            {
-                if (add_prefix)
-                {
-                    oa->write_character(to_char_type('['));
+                    ptr = &ptr->operator[](reference_token);
+                    break;
                 }
 
-                bool prefix_required = true;
-                if (use_type and not j.m_value.array->empty())
+                case detail::value_t::array:
                 {
-                    assert(use_count);
-                    const CharType first_prefix = ubjson_prefix(j.front());
-                    const bool same_prefix = std::all_of(j.begin() + 1, j.end(),
-                                                         [this, first_prefix](const BasicJsonType & v)
+                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
                     {
-                        return ubjson_prefix(v) == first_prefix;
-                    });
+                        // "-" always fails the range check
+                        return false;
+                    }
+                    if (JSON_HEDLEY_UNLIKELY(reference_token.size() == 1 && !("0" <= reference_token && reference_token <= "9")))
+                    {
+                        // invalid char
+                        return false;
+                    }
+                    if (JSON_HEDLEY_UNLIKELY(reference_token.size() > 1))
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(!('1' <= reference_token[0] && reference_token[0] <= '9')))
+                        {
+                            // first char should be between '1' and '9'
+                            return false;
+                        }
+                        for (std::size_t i = 1; i < reference_token.size(); i++)
+                        {
+                            if (JSON_HEDLEY_UNLIKELY(!('0' <= reference_token[i] && reference_token[i] <= '9')))
+                            {
+                                // other char should be between '0' and '9'
+                                return false;
+                            }
+                        }
+                    }
 
-                    if (same_prefix)
+                    const auto idx = array_index(reference_token);
+                    if (idx >= ptr->size())
                     {
-                        prefix_required = false;
-                        oa->write_character(to_char_type('$'));
-                        oa->write_character(first_prefix);
+                        // index out of range
+                        return false;
                     }
-                }
 
-                if (use_count)
-                {
-                    oa->write_character(to_char_type('#'));
-                    write_number_with_ubjson_prefix(j.m_value.array->size(), true);
+                    ptr = &ptr->operator[](idx);
+                    break;
                 }
 
-                for (const auto& el : *j.m_value.array)
+                case detail::value_t::null:
+                case detail::value_t::string:
+                case detail::value_t::boolean:
+                case detail::value_t::number_integer:
+                case detail::value_t::number_unsigned:
+                case detail::value_t::number_float:
+                case detail::value_t::binary:
+                case detail::value_t::discarded:
+                default:
                 {
-                    write_ubjson(el, use_count, use_type, prefix_required);
+                    // we do not expect primitive values if there is still a
+                    // reference token to process
+                    return false;
                 }
+            }
+        }
 
-                if (not use_count)
-                {
-                    oa->write_character(to_char_type(']'));
-                }
+        // no reference token left means we found a primitive value
+        return true;
+    }
 
-                break;
-            }
+    /*!
+    @brief split the string input to reference tokens
 
-            case value_t::object:
+    @note This function is only called by the json_pointer constructor.
+          All exceptions below are documented there.
+
+    @throw parse_error.107  if the pointer is not empty or begins with '/'
+    @throw parse_error.108  if character '~' is not followed by '0' or '1'
+    */
+    static std::vector<std::string> split(const std::string& reference_string)
+    {
+        std::vector<std::string> result;
+
+        // special case: empty reference string -> no reference tokens
+        if (reference_string.empty())
+        {
+            return result;
+        }
+
+        // check if nonempty reference string begins with slash
+        if (JSON_HEDLEY_UNLIKELY(reference_string[0] != '/'))
+        {
+            JSON_THROW(detail::parse_error::create(107, 1, "JSON pointer must be empty or begin with '/' - was: '" + reference_string + "'", BasicJsonType()));
+        }
+
+        // extract the reference tokens:
+        // - slash: position of the last read slash (or end of string)
+        // - start: position after the previous slash
+        for (
+            // search for the first slash after the first character
+            std::size_t slash = reference_string.find_first_of('/', 1),
+            // set the beginning of the first reference token
+            start = 1;
+            // we can stop if start == 0 (if slash == std::string::npos)
+            start != 0;
+            // set the beginning of the next reference token
+            // (will eventually be 0 if slash == std::string::npos)
+            start = (slash == std::string::npos) ? 0 : slash + 1,
+            // find next slash
+            slash = reference_string.find_first_of('/', start))
+        {
+            // use the text between the beginning of the reference token
+            // (start) and the last slash (slash).
+            auto reference_token = reference_string.substr(start, slash - start);
+
+            // check reference tokens are properly escaped
+            for (std::size_t pos = reference_token.find_first_of('~');
+                    pos != std::string::npos;
+                    pos = reference_token.find_first_of('~', pos + 1))
             {
-                if (add_prefix)
+                JSON_ASSERT(reference_token[pos] == '~');
+
+                // ~ must be followed by 0 or 1
+                if (JSON_HEDLEY_UNLIKELY(pos == reference_token.size() - 1 ||
+                                         (reference_token[pos + 1] != '0' &&
+                                          reference_token[pos + 1] != '1')))
                 {
-                    oa->write_character(to_char_type('{'));
+                    JSON_THROW(detail::parse_error::create(108, 0, "escape character '~' must be followed with '0' or '1'", BasicJsonType()));
                 }
+            }
 
-                bool prefix_required = true;
-                if (use_type and not j.m_value.object->empty())
-                {
-                    assert(use_count);
-                    const CharType first_prefix = ubjson_prefix(j.front());
-                    const bool same_prefix = std::all_of(j.begin(), j.end(),
-                                                         [this, first_prefix](const BasicJsonType & v)
-                    {
-                        return ubjson_prefix(v) == first_prefix;
-                    });
+            // finally, store the reference token
+            detail::unescape(reference_token);
+            result.push_back(reference_token);
+        }
 
-                    if (same_prefix)
-                    {
-                        prefix_required = false;
-                        oa->write_character(to_char_type('$'));
-                        oa->write_character(first_prefix);
-                    }
-                }
+        return result;
+    }
 
-                if (use_count)
+  private:
+    /*!
+    @param[in] reference_string  the reference string to the current value
+    @param[in] value             the value to consider
+    @param[in,out] result        the result object to insert values to
+
+    @note Empty objects or arrays are flattened to `null`.
+    */
+    static void flatten(const std::string& reference_string,
+                        const BasicJsonType& value,
+                        BasicJsonType& result)
+    {
+        switch (value.type())
+        {
+            case detail::value_t::array:
+            {
+                if (value.m_value.array->empty())
                 {
-                    oa->write_character(to_char_type('#'));
-                    write_number_with_ubjson_prefix(j.m_value.object->size(), true);
+                    // flatten empty array as null
+                    result[reference_string] = nullptr;
+                }
+                else
+                {
+                    // iterate array and use index as reference string
+                    for (std::size_t i = 0; i < value.m_value.array->size(); ++i)
+                    {
+                        flatten(reference_string + "/" + std::to_string(i),
+                                value.m_value.array->operator[](i), result);
+                    }
                 }
+                break;
+            }
 
-                for (const auto& el : *j.m_value.object)
+            case detail::value_t::object:
+            {
+                if (value.m_value.object->empty())
                 {
-                    write_number_with_ubjson_prefix(el.first.size(), true);
-                    oa->write_characters(
-                        reinterpret_cast<const CharType*>(el.first.c_str()),
-                        el.first.size());
-                    write_ubjson(el.second, use_count, use_type, prefix_required);
+                    // flatten empty object as null
+                    result[reference_string] = nullptr;
                 }
-
-                if (not use_count)
+                else
                 {
-                    oa->write_character(to_char_type('}'));
+                    // iterate object and use keys as reference string
+                    for (const auto& element : *value.m_value.object)
+                    {
+                        flatten(reference_string + "/" + detail::escape(element.first), element.second, result);
+                    }
                 }
-
                 break;
             }
 
+            case detail::value_t::null:
+            case detail::value_t::string:
+            case detail::value_t::boolean:
+            case detail::value_t::number_integer:
+            case detail::value_t::number_unsigned:
+            case detail::value_t::number_float:
+            case detail::value_t::binary:
+            case detail::value_t::discarded:
             default:
+            {
+                // add primitive value with its reference string
+                result[reference_string] = value;
                 break;
+            }
         }
     }
 
-  private:
-    //////////
-    // BSON //
-    //////////
-
     /*!
-    @return The size of a BSON document entry header, including the id marker
-            and the entry name size (and its null-terminator).
+    @param[in] value  flattened JSON
+
+    @return unflattened JSON
+
+    @throw parse_error.109 if array index is not a number
+    @throw type_error.314  if value is not an object
+    @throw type_error.315  if object values are not primitive
+    @throw type_error.313  if value cannot be unflattened
     */
-    static std::size_t calc_bson_entry_header_size(const string_t& name)
+    static BasicJsonType
+    unflatten(const BasicJsonType& value)
     {
-        const auto it = name.find(static_cast<typename string_t::value_type>(0));
-        if (JSON_UNLIKELY(it != BasicJsonType::string_t::npos))
+        if (JSON_HEDLEY_UNLIKELY(!value.is_object()))
         {
-            JSON_THROW(out_of_range::create(409,
-                                            "BSON key cannot contain code point U+0000 (at byte " + std::to_string(it) + ")"));
+            JSON_THROW(detail::type_error::create(314, "only objects can be unflattened", value));
         }
 
-        return /*id*/ 1ul + name.size() + /*zero-terminator*/1u;
+        BasicJsonType result;
+
+        // iterate the JSON object values
+        for (const auto& element : *value.m_value.object)
+        {
+            if (JSON_HEDLEY_UNLIKELY(!element.second.is_primitive()))
+            {
+                JSON_THROW(detail::type_error::create(315, "values in object must be primitive", element.second));
+            }
+
+            // assign value to reference pointed to by JSON pointer; Note that if
+            // the JSON pointer is "" (i.e., points to the whole value), function
+            // get_and_create returns a reference to result itself. An assignment
+            // will then create a primitive value.
+            json_pointer(element.first).get_and_create(result) = element.second;
+        }
+
+        return result;
     }
 
     /*!
-    @brief Writes the given @a element_type and @a name to the output adapter
+    @brief compares two JSON pointers for equality
+
+    @param[in] lhs  JSON pointer to compare
+    @param[in] rhs  JSON pointer to compare
+    @return whether @a lhs is equal to @a rhs
+
+    @complexity Linear in the length of the JSON pointer
+
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
     */
-    void write_bson_entry_header(const string_t& name,
-                                 const std::uint8_t element_type)
+    friend bool operator==(json_pointer const& lhs,
+                           json_pointer const& rhs) noexcept
     {
-        oa->write_character(to_char_type(element_type)); // boolean
-        oa->write_characters(
-            reinterpret_cast<const CharType*>(name.c_str()),
-            name.size() + 1u);
+        return lhs.reference_tokens == rhs.reference_tokens;
     }
 
     /*!
-    @brief Writes a BSON element with key @a name and boolean value @a value
+    @brief compares two JSON pointers for inequality
+
+    @param[in] lhs  JSON pointer to compare
+    @param[in] rhs  JSON pointer to compare
+    @return whether @a lhs is not equal @a rhs
+
+    @complexity Linear in the length of the JSON pointer
+
+    @exceptionsafety No-throw guarantee: this function never throws exceptions.
     */
-    void write_bson_boolean(const string_t& name,
-                            const bool value)
+    friend bool operator!=(json_pointer const& lhs,
+                           json_pointer const& rhs) noexcept
     {
-        write_bson_entry_header(name, 0x08);
-        oa->write_character(value ? to_char_type(0x01) : to_char_type(0x00));
+        return !(lhs == rhs);
     }
 
-    /*!
-    @brief Writes a BSON element with key @a name and double value @a value
-    */
-    void write_bson_double(const string_t& name,
-                           const double value)
+    /// the reference tokens
+    std::vector<std::string> reference_tokens;
+};
+}  // namespace nlohmann
+
+// #include <nlohmann/detail/json_ref.hpp>
+
+
+#include <initializer_list>
+#include <utility>
+
+// #include <nlohmann/detail/meta/type_traits.hpp>
+
+
+namespace nlohmann
+{
+namespace detail
+{
+template<typename BasicJsonType>
+class json_ref
+{
+  public:
+    using value_type = BasicJsonType;
+
+    json_ref(value_type&& value)
+        : owned_value(std::move(value))
+    {}
+
+    json_ref(const value_type& value)
+        : value_ref(&value)
+    {}
+
+    json_ref(std::initializer_list<json_ref> init)
+        : owned_value(init)
+    {}
+
+    template <
+        class... Args,
+        enable_if_t<std::is_constructible<value_type, Args...>::value, int> = 0 >
+    json_ref(Args && ... args)
+        : owned_value(std::forward<Args>(args)...)
+    {}
+
+    // class should be movable only
+    json_ref(json_ref&&) noexcept = default;
+    json_ref(const json_ref&) = delete;
+    json_ref& operator=(const json_ref&) = delete;
+    json_ref& operator=(json_ref&&) = delete;
+    ~json_ref() = default;
+
+    value_type moved_or_copied() const
     {
-        write_bson_entry_header(name, 0x01);
-        write_number<double, true>(value);
+        if (value_ref == nullptr)
+        {
+            return std::move(owned_value);
+        }
+        return *value_ref;
     }
 
-    /*!
-    @return The size of the BSON-encoded string in @a value
-    */
-    static std::size_t calc_bson_string_size(const string_t& value)
+    value_type const& operator*() const
     {
-        return sizeof(std::int32_t) + value.size() + 1ul;
+        return value_ref ? *value_ref : owned_value;
     }
 
-    /*!
-    @brief Writes a BSON element with key @a name and string value @a value
-    */
-    void write_bson_string(const string_t& name,
-                           const string_t& value)
+    value_type const* operator->() const
     {
-        write_bson_entry_header(name, 0x02);
+        return &** this;
+    }
 
-        write_number<std::int32_t, true>(static_cast<std::int32_t>(value.size() + 1ul));
-        oa->write_characters(
-            reinterpret_cast<const CharType*>(value.c_str()),
-            value.size() + 1);
+  private:
+    mutable value_type owned_value = nullptr;
+    value_type const* value_ref = nullptr;
+};
+}  // namespace detail
+}  // namespace nlohmann
+
+// #include <nlohmann/detail/macro_scope.hpp>
+
+// #include <nlohmann/detail/string_escape.hpp>
+
+// #include <nlohmann/detail/meta/cpp_future.hpp>
+
+// #include <nlohmann/detail/meta/type_traits.hpp>
+
+// #include <nlohmann/detail/output/binary_writer.hpp>
+
+
+#include <algorithm> // reverse
+#include <array> // array
+#include <cmath> // isnan, isinf
+#include <cstdint> // uint8_t, uint16_t, uint32_t, uint64_t
+#include <cstring> // memcpy
+#include <limits> // numeric_limits
+#include <string> // string
+#include <utility> // move
+
+// #include <nlohmann/detail/input/binary_reader.hpp>
+
+// #include <nlohmann/detail/macro_scope.hpp>
+
+// #include <nlohmann/detail/output/output_adapters.hpp>
+
+
+#include <algorithm> // copy
+#include <cstddef> // size_t
+#include <iterator> // back_inserter
+#include <memory> // shared_ptr, make_shared
+#include <string> // basic_string
+#include <vector> // vector
+
+#ifndef JSON_NO_IO
+    #include <ios>      // streamsize
+    #include <ostream>  // basic_ostream
+#endif  // JSON_NO_IO
+
+// #include <nlohmann/detail/macro_scope.hpp>
+
+
+namespace nlohmann
+{
+namespace detail
+{
+/// abstract output adapter interface
+template<typename CharType> struct output_adapter_protocol
+{
+    virtual void write_character(CharType c) = 0;
+    virtual void write_characters(const CharType* s, std::size_t length) = 0;
+    virtual ~output_adapter_protocol() = default;
+
+    output_adapter_protocol() = default;
+    output_adapter_protocol(const output_adapter_protocol&) = default;
+    output_adapter_protocol(output_adapter_protocol&&) noexcept = default;
+    output_adapter_protocol& operator=(const output_adapter_protocol&) = default;
+    output_adapter_protocol& operator=(output_adapter_protocol&&) noexcept = default;
+};
+
+/// a type to simplify interfaces
+template<typename CharType>
+using output_adapter_t = std::shared_ptr<output_adapter_protocol<CharType>>;
+
+/// output adapter for byte vectors
+template<typename CharType, typename AllocatorType = std::allocator<CharType>>
+class output_vector_adapter : public output_adapter_protocol<CharType>
+{
+  public:
+    explicit output_vector_adapter(std::vector<CharType, AllocatorType>& vec) noexcept
+        : v(vec)
+    {}
+
+    void write_character(CharType c) override
+    {
+        v.push_back(c);
     }
 
-    /*!
-    @brief Writes a BSON element with key @a name and null value
-    */
-    void write_bson_null(const string_t& name)
+    JSON_HEDLEY_NON_NULL(2)
+    void write_characters(const CharType* s, std::size_t length) override
     {
-        write_bson_entry_header(name, 0x0A);
+        std::copy(s, s + length, std::back_inserter(v));
+    }
+
+  private:
+    std::vector<CharType, AllocatorType>& v;
+};
+
+#ifndef JSON_NO_IO
+/// output adapter for output streams
+template<typename CharType>
+class output_stream_adapter : public output_adapter_protocol<CharType>
+{
+  public:
+    explicit output_stream_adapter(std::basic_ostream<CharType>& s) noexcept
+        : stream(s)
+    {}
+
+    void write_character(CharType c) override
+    {
+        stream.put(c);
     }
 
-    /*!
-    @return The size of the BSON-encoded integer @a value
-    */
-    static std::size_t calc_bson_integer_size(const std::int64_t value)
+    JSON_HEDLEY_NON_NULL(2)
+    void write_characters(const CharType* s, std::size_t length) override
     {
-        if ((std::numeric_limits<std::int32_t>::min)() <= value and value <= (std::numeric_limits<std::int32_t>::max)())
-        {
-            return sizeof(std::int32_t);
-        }
-        else
-        {
-            return sizeof(std::int64_t);
-        }
+        stream.write(s, static_cast<std::streamsize>(length));
     }
 
-    /*!
-    @brief Writes a BSON element with key @a name and integer @a value
-    */
-    void write_bson_integer(const string_t& name,
-                            const std::int64_t value)
+  private:
+    std::basic_ostream<CharType>& stream;
+};
+#endif  // JSON_NO_IO
+
+/// output adapter for basic_string
+template<typename CharType, typename StringType = std::basic_string<CharType>>
+class output_string_adapter : public output_adapter_protocol<CharType>
+{
+  public:
+    explicit output_string_adapter(StringType& s) noexcept
+        : str(s)
+    {}
+
+    void write_character(CharType c) override
     {
-        if ((std::numeric_limits<std::int32_t>::min)() <= value and value <= (std::numeric_limits<std::int32_t>::max)())
-        {
-            write_bson_entry_header(name, 0x10); // int32
-            write_number<std::int32_t, true>(static_cast<std::int32_t>(value));
-        }
-        else
-        {
-            write_bson_entry_header(name, 0x12); // int64
-            write_number<std::int64_t, true>(static_cast<std::int64_t>(value));
-        }
+        str.push_back(c);
     }
 
-    /*!
-    @return The size of the BSON-encoded unsigned integer in @a j
-    */
-    static constexpr std::size_t calc_bson_unsigned_size(const std::uint64_t value) noexcept
+    JSON_HEDLEY_NON_NULL(2)
+    void write_characters(const CharType* s, std::size_t length) override
     {
-        return (value <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
-               ? sizeof(std::int32_t)
-               : sizeof(std::int64_t);
+        str.append(s, length);
     }
 
-    /*!
-    @brief Writes a BSON element with key @a name and unsigned @a value
-    */
-    void write_bson_unsigned(const string_t& name,
-                             const std::uint64_t value)
+  private:
+    StringType& str;
+};
+
+template<typename CharType, typename StringType = std::basic_string<CharType>>
+class output_adapter
+{
+  public:
+    template<typename AllocatorType = std::allocator<CharType>>
+    output_adapter(std::vector<CharType, AllocatorType>& vec)
+        : oa(std::make_shared<output_vector_adapter<CharType, AllocatorType>>(vec)) {}
+
+#ifndef JSON_NO_IO
+    output_adapter(std::basic_ostream<CharType>& s)
+        : oa(std::make_shared<output_stream_adapter<CharType>>(s)) {}
+#endif  // JSON_NO_IO
+
+    output_adapter(StringType& s)
+        : oa(std::make_shared<output_string_adapter<CharType, StringType>>(s)) {}
+
+    operator output_adapter_t<CharType>()
     {
-        if (value <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
-        {
-            write_bson_entry_header(name, 0x10 /* int32 */);
-            write_number<std::int32_t, true>(static_cast<std::int32_t>(value));
-        }
-        else if (value <= static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()))
-        {
-            write_bson_entry_header(name, 0x12 /* int64 */);
-            write_number<std::int64_t, true>(static_cast<std::int64_t>(value));
-        }
-        else
-        {
-            JSON_THROW(out_of_range::create(407, "integer number " + std::to_string(value) + " cannot be represented by BSON as it does not fit int64"));
-        }
+        return oa;
     }
 
+  private:
+    output_adapter_t<CharType> oa = nullptr;
+};
+}  // namespace detail
+}  // namespace nlohmann
+
+
+namespace nlohmann
+{
+namespace detail
+{
+///////////////////
+// binary writer //
+///////////////////
+
+/*!
+@brief serialization to CBOR and MessagePack values
+*/
+template<typename BasicJsonType, typename CharType>
+class binary_writer
+{
+    using string_t = typename BasicJsonType::string_t;
+    using binary_t = typename BasicJsonType::binary_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+
+  public:
     /*!
-    @brief Writes a BSON element with key @a name and object @a value
+    @brief create a binary writer
+
+    @param[in] adapter  output adapter to write to
     */
-    void write_bson_object_entry(const string_t& name,
-                                 const typename BasicJsonType::object_t& value)
+    explicit binary_writer(output_adapter_t<CharType> adapter) : oa(std::move(adapter))
     {
-        write_bson_entry_header(name, 0x03); // object
-        write_bson_object(value);
+        JSON_ASSERT(oa);
     }
 
     /*!
-    @return The size of the BSON-encoded array @a value
+    @param[in] j  JSON value to serialize
+    @pre       j.type() == value_t::object
     */
-    static std::size_t calc_bson_array_size(const typename BasicJsonType::array_t& value)
+    void write_bson(const BasicJsonType& j)
     {
-        std::size_t embedded_document_size = 0ul;
-        std::size_t array_index = 0ul;
-
-        for (const auto& el : value)
+        switch (j.type())
         {
-            embedded_document_size += calc_bson_element_size(std::to_string(array_index++), el);
-        }
+            case value_t::object:
+            {
+                write_bson_object(*j.m_value.object);
+                break;
+            }
 
-        return sizeof(std::int32_t) + embedded_document_size + 1ul;
+            case value_t::null:
+            case value_t::array:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+            {
+                JSON_THROW(type_error::create(317, "to serialize to BSON, top-level type must be object, but is " + std::string(j.type_name()), j));
+            }
+        }
     }
 
     /*!
-    @brief Writes a BSON element with key @a name and array @a value
+    @param[in] j  JSON value to serialize
     */
-    void write_bson_array(const string_t& name,
-                          const typename BasicJsonType::array_t& value)
+    void write_cbor(const BasicJsonType& j)
     {
-        write_bson_entry_header(name, 0x04); // array
-        write_number<std::int32_t, true>(static_cast<std::int32_t>(calc_bson_array_size(value)));
+        switch (j.type())
+        {
+            case value_t::null:
+            {
+                oa->write_character(to_char_type(0xF6));
+                break;
+            }
 
-        std::size_t array_index = 0ul;
+            case value_t::boolean:
+            {
+                oa->write_character(j.m_value.boolean
+                                    ? to_char_type(0xF5)
+                                    : to_char_type(0xF4));
+                break;
+            }
 
-        for (const auto& el : value)
-        {
-            write_bson_element(std::to_string(array_index++), el);
-        }
+            case value_t::number_integer:
+            {
+                if (j.m_value.number_integer >= 0)
+                {
+                    // CBOR does not differentiate between positive signed
+                    // integers and unsigned integers. Therefore, we used the
+                    // code from the value_t::number_unsigned case here.
+                    if (j.m_value.number_integer <= 0x17)
+                    {
+                        write_number(static_cast<std::uint8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer <= (std::numeric_limits<std::uint8_t>::max)())
+                    {
+                        oa->write_character(to_char_type(0x18));
+                        write_number(static_cast<std::uint8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer <= (std::numeric_limits<std::uint16_t>::max)())
+                    {
+                        oa->write_character(to_char_type(0x19));
+                        write_number(static_cast<std::uint16_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer <= (std::numeric_limits<std::uint32_t>::max)())
+                    {
+                        oa->write_character(to_char_type(0x1A));
+                        write_number(static_cast<std::uint32_t>(j.m_value.number_integer));
+                    }
+                    else
+                    {
+                        oa->write_character(to_char_type(0x1B));
+                        write_number(static_cast<std::uint64_t>(j.m_value.number_integer));
+                    }
+                }
+                else
+                {
+                    // The conversions below encode the sign in the first
+                    // byte, and the value is converted to a positive number.
+                    const auto positive_number = -1 - j.m_value.number_integer;
+                    if (j.m_value.number_integer >= -24)
+                    {
+                        write_number(static_cast<std::uint8_t>(0x20 + positive_number));
+                    }
+                    else if (positive_number <= (std::numeric_limits<std::uint8_t>::max)())
+                    {
+                        oa->write_character(to_char_type(0x38));
+                        write_number(static_cast<std::uint8_t>(positive_number));
+                    }
+                    else if (positive_number <= (std::numeric_limits<std::uint16_t>::max)())
+                    {
+                        oa->write_character(to_char_type(0x39));
+                        write_number(static_cast<std::uint16_t>(positive_number));
+                    }
+                    else if (positive_number <= (std::numeric_limits<std::uint32_t>::max)())
+                    {
+                        oa->write_character(to_char_type(0x3A));
+                        write_number(static_cast<std::uint32_t>(positive_number));
+                    }
+                    else
+                    {
+                        oa->write_character(to_char_type(0x3B));
+                        write_number(static_cast<std::uint64_t>(positive_number));
+                    }
+                }
+                break;
+            }
 
-        oa->write_character(to_char_type(0x00));
-    }
+            case value_t::number_unsigned:
+            {
+                if (j.m_value.number_unsigned <= 0x17)
+                {
+                    write_number(static_cast<std::uint8_t>(j.m_value.number_unsigned));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x18));
+                    write_number(static_cast<std::uint8_t>(j.m_value.number_unsigned));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x19));
+                    write_number(static_cast<std::uint16_t>(j.m_value.number_unsigned));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x1A));
+                    write_number(static_cast<std::uint32_t>(j.m_value.number_unsigned));
+                }
+                else
+                {
+                    oa->write_character(to_char_type(0x1B));
+                    write_number(static_cast<std::uint64_t>(j.m_value.number_unsigned));
+                }
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                if (std::isnan(j.m_value.number_float))
+                {
+                    // NaN is 0xf97e00 in CBOR
+                    oa->write_character(to_char_type(0xF9));
+                    oa->write_character(to_char_type(0x7E));
+                    oa->write_character(to_char_type(0x00));
+                }
+                else if (std::isinf(j.m_value.number_float))
+                {
+                    // Infinity is 0xf97c00, -Infinity is 0xf9fc00
+                    oa->write_character(to_char_type(0xf9));
+                    oa->write_character(j.m_value.number_float > 0 ? to_char_type(0x7C) : to_char_type(0xFC));
+                    oa->write_character(to_char_type(0x00));
+                }
+                else
+                {
+                    write_compact_float(j.m_value.number_float, detail::input_format_t::cbor);
+                }
+                break;
+            }
+
+            case value_t::string:
+            {
+                // step 1: write control byte and the string length
+                const auto N = j.m_value.string->size();
+                if (N <= 0x17)
+                {
+                    write_number(static_cast<std::uint8_t>(0x60 + N));
+                }
+                else if (N <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x78));
+                    write_number(static_cast<std::uint8_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x79));
+                    write_number(static_cast<std::uint16_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x7A));
+                    write_number(static_cast<std::uint32_t>(N));
+                }
+                // LCOV_EXCL_START
+                else if (N <= (std::numeric_limits<std::uint64_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x7B));
+                    write_number(static_cast<std::uint64_t>(N));
+                }
+                // LCOV_EXCL_STOP
 
-    /*!
-    @brief Calculates the size necessary to serialize the JSON value @a j with its @a name
-    @return The calculated size for the BSON document entry for @a j with the given @a name.
-    */
-    static std::size_t calc_bson_element_size(const string_t& name,
-            const BasicJsonType& j)
-    {
-        const auto header_size = calc_bson_entry_header_size(name);
-        switch (j.type())
-        {
-            case value_t::object:
-                return header_size + calc_bson_object_size(*j.m_value.object);
+                // step 2: write the string
+                oa->write_characters(
+                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
+                    j.m_value.string->size());
+                break;
+            }
 
             case value_t::array:
-                return header_size + calc_bson_array_size(*j.m_value.array);
+            {
+                // step 1: write control byte and the array size
+                const auto N = j.m_value.array->size();
+                if (N <= 0x17)
+                {
+                    write_number(static_cast<std::uint8_t>(0x80 + N));
+                }
+                else if (N <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x98));
+                    write_number(static_cast<std::uint8_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x99));
+                    write_number(static_cast<std::uint16_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x9A));
+                    write_number(static_cast<std::uint32_t>(N));
+                }
+                // LCOV_EXCL_START
+                else if (N <= (std::numeric_limits<std::uint64_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x9B));
+                    write_number(static_cast<std::uint64_t>(N));
+                }
+                // LCOV_EXCL_STOP
 
-            case value_t::boolean:
-                return header_size + 1ul;
+                // step 2: write each element
+                for (const auto& el : *j.m_value.array)
+                {
+                    write_cbor(el);
+                }
+                break;
+            }
 
-            case value_t::number_float:
-                return header_size + 8ul;
+            case value_t::binary:
+            {
+                if (j.m_value.binary->has_subtype())
+                {
+                    if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint8_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xd8));
+                        write_number(static_cast<std::uint8_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint16_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xd9));
+                        write_number(static_cast<std::uint16_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint32_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xda));
+                        write_number(static_cast<std::uint32_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint64_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xdb));
+                        write_number(static_cast<std::uint64_t>(j.m_value.binary->subtype()));
+                    }
+                }
 
-            case value_t::number_integer:
-                return header_size + calc_bson_integer_size(j.m_value.number_integer);
+                // step 1: write control byte and the binary array size
+                const auto N = j.m_value.binary->size();
+                if (N <= 0x17)
+                {
+                    write_number(static_cast<std::uint8_t>(0x40 + N));
+                }
+                else if (N <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x58));
+                    write_number(static_cast<std::uint8_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x59));
+                    write_number(static_cast<std::uint16_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x5A));
+                    write_number(static_cast<std::uint32_t>(N));
+                }
+                // LCOV_EXCL_START
+                else if (N <= (std::numeric_limits<std::uint64_t>::max)())
+                {
+                    oa->write_character(to_char_type(0x5B));
+                    write_number(static_cast<std::uint64_t>(N));
+                }
+                // LCOV_EXCL_STOP
 
-            case value_t::number_unsigned:
-                return header_size + calc_bson_unsigned_size(j.m_value.number_unsigned);
+                // step 2: write each element
+                oa->write_characters(
+                    reinterpret_cast<const CharType*>(j.m_value.binary->data()),
+                    N);
 
-            case value_t::string:
-                return header_size + calc_bson_string_size(*j.m_value.string);
+                break;
+            }
 
-            case value_t::null:
-                return header_size + 0ul;
+            case value_t::object:
+            {
+                // step 1: write control byte and the object size
+                const auto N = j.m_value.object->size();
+                if (N <= 0x17)
+                {
+                    write_number(static_cast<std::uint8_t>(0xA0 + N));
+                }
+                else if (N <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    oa->write_character(to_char_type(0xB8));
+                    write_number(static_cast<std::uint8_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    oa->write_character(to_char_type(0xB9));
+                    write_number(static_cast<std::uint16_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    oa->write_character(to_char_type(0xBA));
+                    write_number(static_cast<std::uint32_t>(N));
+                }
+                // LCOV_EXCL_START
+                else if (N <= (std::numeric_limits<std::uint64_t>::max)())
+                {
+                    oa->write_character(to_char_type(0xBB));
+                    write_number(static_cast<std::uint64_t>(N));
+                }
+                // LCOV_EXCL_STOP
 
-            // LCOV_EXCL_START
+                // step 2: write each element
+                for (const auto& el : *j.m_value.object)
+                {
+                    write_cbor(el.first);
+                    write_cbor(el.second);
+                }
+                break;
+            }
+
+            case value_t::discarded:
             default:
-                assert(false);
-                return 0ul;
-                // LCOV_EXCL_STOP
-        };
+                break;
+        }
     }
 
     /*!
-    @brief Serializes the JSON value @a j to BSON and associates it with the
-           key @a name.
-    @param name The name to associate with the JSON entity @a j within the
-                current BSON document
-    @return The size of the BSON entry
+    @param[in] j  JSON value to serialize
     */
-    void write_bson_element(const string_t& name,
-                            const BasicJsonType& j)
+    void write_msgpack(const BasicJsonType& j)
     {
         switch (j.type())
         {
-            case value_t::object:
-                return write_bson_object_entry(name, *j.m_value.object);
-
-            case value_t::array:
-                return write_bson_array(name, *j.m_value.array);
-
-            case value_t::boolean:
-                return write_bson_boolean(name, j.m_value.boolean);
+            case value_t::null: // nil
+            {
+                oa->write_character(to_char_type(0xC0));
+                break;
+            }
 
-            case value_t::number_float:
-                return write_bson_double(name, j.m_value.number_float);
+            case value_t::boolean: // true and false
+            {
+                oa->write_character(j.m_value.boolean
+                                    ? to_char_type(0xC3)
+                                    : to_char_type(0xC2));
+                break;
+            }
 
             case value_t::number_integer:
-                return write_bson_integer(name, j.m_value.number_integer);
+            {
+                if (j.m_value.number_integer >= 0)
+                {
+                    // MessagePack does not differentiate between positive
+                    // signed integers and unsigned integers. Therefore, we used
+                    // the code from the value_t::number_unsigned case here.
+                    if (j.m_value.number_unsigned < 128)
+                    {
+                        // positive fixnum
+                        write_number(static_cast<std::uint8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint8_t>::max)())
+                    {
+                        // uint 8
+                        oa->write_character(to_char_type(0xCC));
+                        write_number(static_cast<std::uint8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint16_t>::max)())
+                    {
+                        // uint 16
+                        oa->write_character(to_char_type(0xCD));
+                        write_number(static_cast<std::uint16_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint32_t>::max)())
+                    {
+                        // uint 32
+                        oa->write_character(to_char_type(0xCE));
+                        write_number(static_cast<std::uint32_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint64_t>::max)())
+                    {
+                        // uint 64
+                        oa->write_character(to_char_type(0xCF));
+                        write_number(static_cast<std::uint64_t>(j.m_value.number_integer));
+                    }
+                }
+                else
+                {
+                    if (j.m_value.number_integer >= -32)
+                    {
+                        // negative fixnum
+                        write_number(static_cast<std::int8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer >= (std::numeric_limits<std::int8_t>::min)() &&
+                             j.m_value.number_integer <= (std::numeric_limits<std::int8_t>::max)())
+                    {
+                        // int 8
+                        oa->write_character(to_char_type(0xD0));
+                        write_number(static_cast<std::int8_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer >= (std::numeric_limits<std::int16_t>::min)() &&
+                             j.m_value.number_integer <= (std::numeric_limits<std::int16_t>::max)())
+                    {
+                        // int 16
+                        oa->write_character(to_char_type(0xD1));
+                        write_number(static_cast<std::int16_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer >= (std::numeric_limits<std::int32_t>::min)() &&
+                             j.m_value.number_integer <= (std::numeric_limits<std::int32_t>::max)())
+                    {
+                        // int 32
+                        oa->write_character(to_char_type(0xD2));
+                        write_number(static_cast<std::int32_t>(j.m_value.number_integer));
+                    }
+                    else if (j.m_value.number_integer >= (std::numeric_limits<std::int64_t>::min)() &&
+                             j.m_value.number_integer <= (std::numeric_limits<std::int64_t>::max)())
+                    {
+                        // int 64
+                        oa->write_character(to_char_type(0xD3));
+                        write_number(static_cast<std::int64_t>(j.m_value.number_integer));
+                    }
+                }
+                break;
+            }
 
             case value_t::number_unsigned:
-                return write_bson_unsigned(name, j.m_value.number_unsigned);
+            {
+                if (j.m_value.number_unsigned < 128)
+                {
+                    // positive fixnum
+                    write_number(static_cast<std::uint8_t>(j.m_value.number_integer));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    // uint 8
+                    oa->write_character(to_char_type(0xCC));
+                    write_number(static_cast<std::uint8_t>(j.m_value.number_integer));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    // uint 16
+                    oa->write_character(to_char_type(0xCD));
+                    write_number(static_cast<std::uint16_t>(j.m_value.number_integer));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    // uint 32
+                    oa->write_character(to_char_type(0xCE));
+                    write_number(static_cast<std::uint32_t>(j.m_value.number_integer));
+                }
+                else if (j.m_value.number_unsigned <= (std::numeric_limits<std::uint64_t>::max)())
+                {
+                    // uint 64
+                    oa->write_character(to_char_type(0xCF));
+                    write_number(static_cast<std::uint64_t>(j.m_value.number_integer));
+                }
+                break;
+            }
+
+            case value_t::number_float:
+            {
+                write_compact_float(j.m_value.number_float, detail::input_format_t::msgpack);
+                break;
+            }
 
             case value_t::string:
-                return write_bson_string(name, *j.m_value.string);
+            {
+                // step 1: write control byte and the string length
+                const auto N = j.m_value.string->size();
+                if (N <= 31)
+                {
+                    // fixstr
+                    write_number(static_cast<std::uint8_t>(0xA0 | N));
+                }
+                else if (N <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    // str 8
+                    oa->write_character(to_char_type(0xD9));
+                    write_number(static_cast<std::uint8_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    // str 16
+                    oa->write_character(to_char_type(0xDA));
+                    write_number(static_cast<std::uint16_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    // str 32
+                    oa->write_character(to_char_type(0xDB));
+                    write_number(static_cast<std::uint32_t>(N));
+                }
 
-            case value_t::null:
-                return write_bson_null(name);
+                // step 2: write the string
+                oa->write_characters(
+                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
+                    j.m_value.string->size());
+                break;
+            }
 
-            // LCOV_EXCL_START
-            default:
-                assert(false);
-                return;
-                // LCOV_EXCL_STOP
-        };
-    }
+            case value_t::array:
+            {
+                // step 1: write control byte and the array size
+                const auto N = j.m_value.array->size();
+                if (N <= 15)
+                {
+                    // fixarray
+                    write_number(static_cast<std::uint8_t>(0x90 | N));
+                }
+                else if (N <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    // array 16
+                    oa->write_character(to_char_type(0xDC));
+                    write_number(static_cast<std::uint16_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    // array 32
+                    oa->write_character(to_char_type(0xDD));
+                    write_number(static_cast<std::uint32_t>(N));
+                }
 
-    /*!
-    @brief Calculates the size of the BSON serialization of the given
-           JSON-object @a j.
-    @param[in] j  JSON value to serialize
-    @pre       j.type() == value_t::object
-    */
-    static std::size_t calc_bson_object_size(const typename BasicJsonType::object_t& value)
-    {
-        std::size_t document_size = std::accumulate(value.begin(), value.end(), 0ul,
-                                    [](size_t result, const typename BasicJsonType::object_t::value_type & el)
-        {
-            return result += calc_bson_element_size(el.first, el.second);
-        });
+                // step 2: write each element
+                for (const auto& el : *j.m_value.array)
+                {
+                    write_msgpack(el);
+                }
+                break;
+            }
 
-        return sizeof(std::int32_t) + document_size + 1ul;
-    }
+            case value_t::binary:
+            {
+                // step 0: determine if the binary type has a set subtype to
+                // determine whether or not to use the ext or fixext types
+                const bool use_ext = j.m_value.binary->has_subtype();
 
-    /*!
-    @param[in] j  JSON value to serialize
-    @pre       j.type() == value_t::object
-    */
-    void write_bson_object(const typename BasicJsonType::object_t& value)
-    {
-        write_number<std::int32_t, true>(static_cast<std::int32_t>(calc_bson_object_size(value)));
+                // step 1: write control byte and the byte string length
+                const auto N = j.m_value.binary->size();
+                if (N <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    std::uint8_t output_type{};
+                    bool fixed = true;
+                    if (use_ext)
+                    {
+                        switch (N)
+                        {
+                            case 1:
+                                output_type = 0xD4; // fixext 1
+                                break;
+                            case 2:
+                                output_type = 0xD5; // fixext 2
+                                break;
+                            case 4:
+                                output_type = 0xD6; // fixext 4
+                                break;
+                            case 8:
+                                output_type = 0xD7; // fixext 8
+                                break;
+                            case 16:
+                                output_type = 0xD8; // fixext 16
+                                break;
+                            default:
+                                output_type = 0xC7; // ext 8
+                                fixed = false;
+                                break;
+                        }
 
-        for (const auto& el : value)
-        {
-            write_bson_element(el.first, el.second);
-        }
+                    }
+                    else
+                    {
+                        output_type = 0xC4; // bin 8
+                        fixed = false;
+                    }
 
-        oa->write_character(to_char_type(0x00));
-    }
+                    oa->write_character(to_char_type(output_type));
+                    if (!fixed)
+                    {
+                        write_number(static_cast<std::uint8_t>(N));
+                    }
+                }
+                else if (N <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    std::uint8_t output_type = use_ext
+                                               ? 0xC8 // ext 16
+                                               : 0xC5; // bin 16
 
-    //////////
-    // CBOR //
-    //////////
+                    oa->write_character(to_char_type(output_type));
+                    write_number(static_cast<std::uint16_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    std::uint8_t output_type = use_ext
+                                               ? 0xC9 // ext 32
+                                               : 0xC6; // bin 32
 
-    static constexpr CharType get_cbor_float_prefix(float /*unused*/)
-    {
-        return to_char_type(0xFA);  // Single-Precision Float
-    }
+                    oa->write_character(to_char_type(output_type));
+                    write_number(static_cast<std::uint32_t>(N));
+                }
 
-    static constexpr CharType get_cbor_float_prefix(double /*unused*/)
-    {
-        return to_char_type(0xFB);  // Double-Precision Float
-    }
+                // step 1.5: if this is an ext type, write the subtype
+                if (use_ext)
+                {
+                    write_number(static_cast<std::int8_t>(j.m_value.binary->subtype()));
+                }
 
-    /////////////
-    // MsgPack //
-    /////////////
+                // step 2: write the byte string
+                oa->write_characters(
+                    reinterpret_cast<const CharType*>(j.m_value.binary->data()),
+                    N);
 
-    static constexpr CharType get_msgpack_float_prefix(float /*unused*/)
-    {
-        return to_char_type(0xCA);  // float 32
-    }
+                break;
+            }
 
-    static constexpr CharType get_msgpack_float_prefix(double /*unused*/)
-    {
-        return to_char_type(0xCB);  // float 64
-    }
+            case value_t::object:
+            {
+                // step 1: write control byte and the object size
+                const auto N = j.m_value.object->size();
+                if (N <= 15)
+                {
+                    // fixmap
+                    write_number(static_cast<std::uint8_t>(0x80 | (N & 0xF)));
+                }
+                else if (N <= (std::numeric_limits<std::uint16_t>::max)())
+                {
+                    // map 16
+                    oa->write_character(to_char_type(0xDE));
+                    write_number(static_cast<std::uint16_t>(N));
+                }
+                else if (N <= (std::numeric_limits<std::uint32_t>::max)())
+                {
+                    // map 32
+                    oa->write_character(to_char_type(0xDF));
+                    write_number(static_cast<std::uint32_t>(N));
+                }
 
-    ////////////
-    // UBJSON //
-    ////////////
+                // step 2: write each element
+                for (const auto& el : *j.m_value.object)
+                {
+                    write_msgpack(el.first);
+                    write_msgpack(el.second);
+                }
+                break;
+            }
 
-    // UBJSON: write number (floating point)
-    template<typename NumberType, typename std::enable_if<
-                 std::is_floating_point<NumberType>::value, int>::type = 0>
-    void write_number_with_ubjson_prefix(const NumberType n,
-                                         const bool add_prefix)
-    {
-        if (add_prefix)
-        {
-            oa->write_character(get_ubjson_float_prefix(n));
+            case value_t::discarded:
+            default:
+                break;
         }
-        write_number(n);
     }
 
-    // UBJSON: write number (unsigned integer)
-    template<typename NumberType, typename std::enable_if<
-                 std::is_unsigned<NumberType>::value, int>::type = 0>
-    void write_number_with_ubjson_prefix(const NumberType n,
-                                         const bool add_prefix)
+    /*!
+    @param[in] j  JSON value to serialize
+    @param[in] use_count   whether to use '#' prefixes (optimized format)
+    @param[in] use_type    whether to use '$' prefixes (optimized format)
+    @param[in] add_prefix  whether prefixes need to be used for this value
+    */
+    void write_ubjson(const BasicJsonType& j, const bool use_count,
+                      const bool use_type, const bool add_prefix = true)
     {
-        if (n <= static_cast<uint64_t>((std::numeric_limits<int8_t>::max)()))
-        {
-            if (add_prefix)
-            {
-                oa->write_character(to_char_type('i'));  // int8
-            }
-            write_number(static_cast<uint8_t>(n));
-        }
-        else if (n <= (std::numeric_limits<uint8_t>::max)())
-        {
-            if (add_prefix)
-            {
-                oa->write_character(to_char_type('U'));  // uint8
-            }
-            write_number(static_cast<uint8_t>(n));
-        }
-        else if (n <= static_cast<uint64_t>((std::numeric_limits<int16_t>::max)()))
-        {
-            if (add_prefix)
-            {
-                oa->write_character(to_char_type('I'));  // int16
-            }
-            write_number(static_cast<int16_t>(n));
-        }
-        else if (n <= static_cast<uint64_t>((std::numeric_limits<int32_t>::max)()))
-        {
-            if (add_prefix)
-            {
-                oa->write_character(to_char_type('l'));  // int32
-            }
-            write_number(static_cast<int32_t>(n));
-        }
-        else if (n <= static_cast<uint64_t>((std::numeric_limits<int64_t>::max)()))
+        switch (j.type())
         {
-            if (add_prefix)
+            case value_t::null:
             {
-                oa->write_character(to_char_type('L'));  // int64
+                if (add_prefix)
+                {
+                    oa->write_character(to_char_type('Z'));
+                }
+                break;
             }
-            write_number(static_cast<int64_t>(n));
-        }
-        else
-        {
-            JSON_THROW(out_of_range::create(407, "integer number " + std::to_string(n) + " cannot be represented by UBJSON as it does not fit int64"));
-        }
-    }
 
-    // UBJSON: write number (signed integer)
-    template<typename NumberType, typename std::enable_if<
-                 std::is_signed<NumberType>::value and
-                 not std::is_floating_point<NumberType>::value, int>::type = 0>
-    void write_number_with_ubjson_prefix(const NumberType n,
-                                         const bool add_prefix)
-    {
-        if ((std::numeric_limits<int8_t>::min)() <= n and n <= (std::numeric_limits<int8_t>::max)())
-        {
-            if (add_prefix)
+            case value_t::boolean:
             {
-                oa->write_character(to_char_type('i'));  // int8
+                if (add_prefix)
+                {
+                    oa->write_character(j.m_value.boolean
+                                        ? to_char_type('T')
+                                        : to_char_type('F'));
+                }
+                break;
             }
-            write_number(static_cast<int8_t>(n));
-        }
-        else if (static_cast<int64_t>((std::numeric_limits<uint8_t>::min)()) <= n and n <= static_cast<int64_t>((std::numeric_limits<uint8_t>::max)()))
-        {
-            if (add_prefix)
+
+            case value_t::number_integer:
             {
-                oa->write_character(to_char_type('U'));  // uint8
+                write_number_with_ubjson_prefix(j.m_value.number_integer, add_prefix);
+                break;
             }
-            write_number(static_cast<uint8_t>(n));
-        }
-        else if ((std::numeric_limits<int16_t>::min)() <= n and n <= (std::numeric_limits<int16_t>::max)())
-        {
-            if (add_prefix)
+
+            case value_t::number_unsigned:
             {
-                oa->write_character(to_char_type('I'));  // int16
+                write_number_with_ubjson_prefix(j.m_value.number_unsigned, add_prefix);
+                break;
             }
-            write_number(static_cast<int16_t>(n));
-        }
-        else if ((std::numeric_limits<int32_t>::min)() <= n and n <= (std::numeric_limits<int32_t>::max)())
-        {
-            if (add_prefix)
+
+            case value_t::number_float:
             {
-                oa->write_character(to_char_type('l'));  // int32
+                write_number_with_ubjson_prefix(j.m_value.number_float, add_prefix);
+                break;
             }
-            write_number(static_cast<int32_t>(n));
-        }
-        else if ((std::numeric_limits<int64_t>::min)() <= n and n <= (std::numeric_limits<int64_t>::max)())
-        {
-            if (add_prefix)
+
+            case value_t::string:
             {
-                oa->write_character(to_char_type('L'));  // int64
+                if (add_prefix)
+                {
+                    oa->write_character(to_char_type('S'));
+                }
+                write_number_with_ubjson_prefix(j.m_value.string->size(), true);
+                oa->write_characters(
+                    reinterpret_cast<const CharType*>(j.m_value.string->c_str()),
+                    j.m_value.string->size());
+                break;
             }
-            write_number(static_cast<int64_t>(n));
-        }
-        // LCOV_EXCL_START
-        else
-        {
-            JSON_THROW(out_of_range::create(407, "integer number " + std::to_string(n) + " cannot be represented by UBJSON as it does not fit int64"));
-        }
-        // LCOV_EXCL_STOP
-    }
 
-    /*!
-    @brief determine the type prefix of container values
+            case value_t::array:
+            {
+                if (add_prefix)
+                {
+                    oa->write_character(to_char_type('['));
+                }
 
-    @note This function does not need to be 100% accurate when it comes to
-          integer limits. In case a number exceeds the limits of int64_t,
-          this will be detected by a later call to function
-          write_number_with_ubjson_prefix. Therefore, we return 'L' for any
-          value that does not fit the previous limits.
-    */
-    CharType ubjson_prefix(const BasicJsonType& j) const noexcept
-    {
-        switch (j.type())
-        {
-            case value_t::null:
-                return 'Z';
+                bool prefix_required = true;
+                if (use_type && !j.m_value.array->empty())
+                {
+                    JSON_ASSERT(use_count);
+                    const CharType first_prefix = ubjson_prefix(j.front());
+                    const bool same_prefix = std::all_of(j.begin() + 1, j.end(),
+                                                         [this, first_prefix](const BasicJsonType & v)
+                    {
+                        return ubjson_prefix(v) == first_prefix;
+                    });
 
-            case value_t::boolean:
-                return j.m_value.boolean ? 'T' : 'F';
+                    if (same_prefix)
+                    {
+                        prefix_required = false;
+                        oa->write_character(to_char_type('$'));
+                        oa->write_character(first_prefix);
+                    }
+                }
 
-            case value_t::number_integer:
+                if (use_count)
+                {
+                    oa->write_character(to_char_type('#'));
+                    write_number_with_ubjson_prefix(j.m_value.array->size(), true);
+                }
+
+                for (const auto& el : *j.m_value.array)
+                {
+                    write_ubjson(el, use_count, use_type, prefix_required);
+                }
+
+                if (!use_count)
+                {
+                    oa->write_character(to_char_type(']'));
+                }
+
+                break;
+            }
+
+            case value_t::binary:
             {
-                if ((std::numeric_limits<int8_t>::min)() <= j.m_value.number_integer and j.m_value.number_integer <= (std::numeric_limits<int8_t>::max)())
+                if (add_prefix)
                 {
-                    return 'i';
+                    oa->write_character(to_char_type('['));
                 }
-                if ((std::numeric_limits<uint8_t>::min)() <= j.m_value.number_integer and j.m_value.number_integer <= (std::numeric_limits<uint8_t>::max)())
+
+                if (use_type && !j.m_value.binary->empty())
                 {
-                    return 'U';
+                    JSON_ASSERT(use_count);
+                    oa->write_character(to_char_type('$'));
+                    oa->write_character('U');
                 }
-                if ((std::numeric_limits<int16_t>::min)() <= j.m_value.number_integer and j.m_value.number_integer <= (std::numeric_limits<int16_t>::max)())
+
+                if (use_count)
                 {
-                    return 'I';
+                    oa->write_character(to_char_type('#'));
+                    write_number_with_ubjson_prefix(j.m_value.binary->size(), true);
                 }
-                if ((std::numeric_limits<int32_t>::min)() <= j.m_value.number_integer and j.m_value.number_integer <= (std::numeric_limits<int32_t>::max)())
+
+                if (use_type)
                 {
-                    return 'l';
+                    oa->write_characters(
+                        reinterpret_cast<const CharType*>(j.m_value.binary->data()),
+                        j.m_value.binary->size());
                 }
-                // no check and assume int64_t (see note above)
-                return 'L';
+                else
+                {
+                    for (size_t i = 0; i < j.m_value.binary->size(); ++i)
+                    {
+                        oa->write_character(to_char_type('U'));
+                        oa->write_character(j.m_value.binary->data()[i]);
+                    }
+                }
+
+                if (!use_count)
+                {
+                    oa->write_character(to_char_type(']'));
+                }
+
+                break;
             }
 
-            case value_t::number_unsigned:
+            case value_t::object:
             {
-                if (j.m_value.number_unsigned <= (std::numeric_limits<int8_t>::max)())
+                if (add_prefix)
                 {
-                    return 'i';
+                    oa->write_character(to_char_type('{'));
                 }
-                if (j.m_value.number_unsigned <= (std::numeric_limits<uint8_t>::max)())
+
+                bool prefix_required = true;
+                if (use_type && !j.m_value.object->empty())
                 {
-                    return 'U';
+                    JSON_ASSERT(use_count);
+                    const CharType first_prefix = ubjson_prefix(j.front());
+                    const bool same_prefix = std::all_of(j.begin(), j.end(),
+                                                         [this, first_prefix](const BasicJsonType & v)
+                    {
+                        return ubjson_prefix(v) == first_prefix;
+                    });
+
+                    if (same_prefix)
+                    {
+                        prefix_required = false;
+                        oa->write_character(to_char_type('$'));
+                        oa->write_character(first_prefix);
+                    }
                 }
-                if (j.m_value.number_unsigned <= (std::numeric_limits<int16_t>::max)())
+
+                if (use_count)
                 {
-                    return 'I';
+                    oa->write_character(to_char_type('#'));
+                    write_number_with_ubjson_prefix(j.m_value.object->size(), true);
                 }
-                if (j.m_value.number_unsigned <= (std::numeric_limits<int32_t>::max)())
+
+                for (const auto& el : *j.m_value.object)
                 {
-                    return 'l';
+                    write_number_with_ubjson_prefix(el.first.size(), true);
+                    oa->write_characters(
+                        reinterpret_cast<const CharType*>(el.first.c_str()),
+                        el.first.size());
+                    write_ubjson(el.second, use_count, use_type, prefix_required);
                 }
-                // no check and assume int64_t (see note above)
-                return 'L';
-            }
 
-            case value_t::number_float:
-                return get_ubjson_float_prefix(j.m_value.number_float);
+                if (!use_count)
+                {
+                    oa->write_character(to_char_type('}'));
+                }
 
-            case value_t::string:
-                return 'S';
+                break;
+            }
 
-            case value_t::array:
-                return '[';
+            case value_t::discarded:
+            default:
+                break;
+        }
+    }
 
-            case value_t::object:
-                return '{';
+  private:
+    //////////
+    // BSON //
+    //////////
 
-            default:  // discarded values
-                return 'N';
+    /*!
+    @return The size of a BSON document entry header, including the id marker
+            and the entry name size (and its null-terminator).
+    */
+    static std::size_t calc_bson_entry_header_size(const string_t& name, const BasicJsonType& j)
+    {
+        const auto it = name.find(static_cast<typename string_t::value_type>(0));
+        if (JSON_HEDLEY_UNLIKELY(it != BasicJsonType::string_t::npos))
+        {
+            JSON_THROW(out_of_range::create(409, "BSON key cannot contain code point U+0000 (at byte " + std::to_string(it) + ")", j));
+            static_cast<void>(j);
         }
+
+        return /*id*/ 1ul + name.size() + /*zero-terminator*/1u;
     }
 
-    static constexpr CharType get_ubjson_float_prefix(float /*unused*/)
+    /*!
+    @brief Writes the given @a element_type and @a name to the output adapter
+    */
+    void write_bson_entry_header(const string_t& name,
+                                 const std::uint8_t element_type)
     {
-        return 'd';  // float 32
+        oa->write_character(to_char_type(element_type)); // boolean
+        oa->write_characters(
+            reinterpret_cast<const CharType*>(name.c_str()),
+            name.size() + 1u);
     }
 
-    static constexpr CharType get_ubjson_float_prefix(double /*unused*/)
+    /*!
+    @brief Writes a BSON element with key @a name and boolean value @a value
+    */
+    void write_bson_boolean(const string_t& name,
+                            const bool value)
     {
-        return 'D';  // float 64
+        write_bson_entry_header(name, 0x08);
+        oa->write_character(value ? to_char_type(0x01) : to_char_type(0x00));
     }
 
-    ///////////////////////
-    // Utility functions //
-    ///////////////////////
+    /*!
+    @brief Writes a BSON element with key @a name and double value @a value
+    */
+    void write_bson_double(const string_t& name,
+                           const double value)
+    {
+        write_bson_entry_header(name, 0x01);
+        write_number<double, true>(value);
+    }
 
-    /*
-    @brief write a number to output input
-    @param[in] n number of type @a NumberType
-    @tparam NumberType the type of the number
-    @tparam OutputIsLittleEndian Set to true if output data is
-                                 required to be little endian
+    /*!
+    @return The size of the BSON-encoded string in @a value
+    */
+    static std::size_t calc_bson_string_size(const string_t& value)
+    {
+        return sizeof(std::int32_t) + value.size() + 1ul;
+    }
 
-    @note This function needs to respect the system's endianess, because bytes
-          in CBOR, MessagePack, and UBJSON are stored in network order (big
-          endian) and therefore need reordering on little endian systems.
+    /*!
+    @brief Writes a BSON element with key @a name and string value @a value
     */
-    template<typename NumberType, bool OutputIsLittleEndian = false>
-    void write_number(const NumberType n)
+    void write_bson_string(const string_t& name,
+                           const string_t& value)
     {
-        // step 1: write number to array of length NumberType
-        std::array<CharType, sizeof(NumberType)> vec;
-        std::memcpy(vec.data(), &n, sizeof(NumberType));
+        write_bson_entry_header(name, 0x02);
 
-        // step 2: write array to output (with possible reordering)
-        if (is_little_endian and not OutputIsLittleEndian)
-        {
-            // reverse byte order prior to conversion if necessary
-            std::reverse(vec.begin(), vec.end());
-        }
+        write_number<std::int32_t, true>(static_cast<std::int32_t>(value.size() + 1ul));
+        oa->write_characters(
+            reinterpret_cast<const CharType*>(value.c_str()),
+            value.size() + 1);
+    }
 
-        oa->write_characters(vec.data(), sizeof(NumberType));
+    /*!
+    @brief Writes a BSON element with key @a name and null value
+    */
+    void write_bson_null(const string_t& name)
+    {
+        write_bson_entry_header(name, 0x0A);
     }
 
-  public:
-    // The following to_char_type functions are implement the conversion
-    // between uint8_t and CharType. In case CharType is not unsigned,
-    // such a conversion is required to allow values greater than 128.
-    // See <https://github.com/nlohmann/json/issues/1286> for a discussion.
-    template < typename C = CharType,
-               enable_if_t < std::is_signed<C>::value and std::is_signed<char>::value > * = nullptr >
-    static constexpr CharType to_char_type(std::uint8_t x) noexcept
+    /*!
+    @return The size of the BSON-encoded integer @a value
+    */
+    static std::size_t calc_bson_integer_size(const std::int64_t value)
     {
-        return *reinterpret_cast<char*>(&x);
+        return (std::numeric_limits<std::int32_t>::min)() <= value && value <= (std::numeric_limits<std::int32_t>::max)()
+               ? sizeof(std::int32_t)
+               : sizeof(std::int64_t);
+    }
+
+    /*!
+    @brief Writes a BSON element with key @a name and integer @a value
+    */
+    void write_bson_integer(const string_t& name,
+                            const std::int64_t value)
+    {
+        if ((std::numeric_limits<std::int32_t>::min)() <= value && value <= (std::numeric_limits<std::int32_t>::max)())
+        {
+            write_bson_entry_header(name, 0x10); // int32
+            write_number<std::int32_t, true>(static_cast<std::int32_t>(value));
+        }
+        else
+        {
+            write_bson_entry_header(name, 0x12); // int64
+            write_number<std::int64_t, true>(static_cast<std::int64_t>(value));
+        }
     }
 
-    template < typename C = CharType,
-               enable_if_t < std::is_signed<C>::value and std::is_unsigned<char>::value > * = nullptr >
-    static CharType to_char_type(std::uint8_t x) noexcept
+    /*!
+    @return The size of the BSON-encoded unsigned integer in @a j
+    */
+    static constexpr std::size_t calc_bson_unsigned_size(const std::uint64_t value) noexcept
     {
-        static_assert(sizeof(std::uint8_t) == sizeof(CharType), "size of CharType must be equal to std::uint8_t");
-        static_assert(std::is_pod<CharType>::value, "CharType must be POD");
-        CharType result;
-        std::memcpy(&result, &x, sizeof(x));
-        return result;
+        return (value <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
+               ? sizeof(std::int32_t)
+               : sizeof(std::int64_t);
     }
 
-    template<typename C = CharType,
-             enable_if_t<std::is_unsigned<C>::value>* = nullptr>
-    static constexpr CharType to_char_type(std::uint8_t x) noexcept
+    /*!
+    @brief Writes a BSON element with key @a name and unsigned @a value
+    */
+    void write_bson_unsigned(const string_t& name,
+                             const BasicJsonType& j)
     {
-        return x;
+        if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
+        {
+            write_bson_entry_header(name, 0x10 /* int32 */);
+            write_number<std::int32_t, true>(static_cast<std::int32_t>(j.m_value.number_unsigned));
+        }
+        else if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()))
+        {
+            write_bson_entry_header(name, 0x12 /* int64 */);
+            write_number<std::int64_t, true>(static_cast<std::int64_t>(j.m_value.number_unsigned));
+        }
+        else
+        {
+            JSON_THROW(out_of_range::create(407, "integer number " + std::to_string(j.m_value.number_unsigned) + " cannot be represented by BSON as it does not fit int64", j));
+        }
     }
 
-    template < typename InputCharType, typename C = CharType,
-               enable_if_t <
-                   std::is_signed<C>::value and
-                   std::is_signed<char>::value and
-                   std::is_same<char, typename std::remove_cv<InputCharType>::type>::value
-                   > * = nullptr >
-    static constexpr CharType to_char_type(InputCharType x) noexcept
+    /*!
+    @brief Writes a BSON element with key @a name and object @a value
+    */
+    void write_bson_object_entry(const string_t& name,
+                                 const typename BasicJsonType::object_t& value)
     {
-        return x;
+        write_bson_entry_header(name, 0x03); // object
+        write_bson_object(value);
     }
 
-  private:
-    /// whether we can assume little endianess
-    const bool is_little_endian = binary_reader<BasicJsonType>::little_endianess();
-
-    /// the output
-    output_adapter_t<CharType> oa = nullptr;
-};
-}  // namespace detail
-}  // namespace nlohmann
+    /*!
+    @return The size of the BSON-encoded array @a value
+    */
+    static std::size_t calc_bson_array_size(const typename BasicJsonType::array_t& value)
+    {
+        std::size_t array_index = 0ul;
 
-// #include <nlohmann/detail/output/serializer.hpp>
+        const std::size_t embedded_document_size = std::accumulate(std::begin(value), std::end(value), std::size_t(0), [&array_index](std::size_t result, const typename BasicJsonType::array_t::value_type & el)
+        {
+            return result + calc_bson_element_size(std::to_string(array_index++), el);
+        });
 
+        return sizeof(std::int32_t) + embedded_document_size + 1ul;
+    }
 
-#include <algorithm> // reverse, remove, fill, find, none_of
-#include <array> // array
-#include <cassert> // assert
-#include <ciso646> // and, or
-#include <clocale> // localeconv, lconv
-#include <cmath> // labs, isfinite, isnan, signbit
-#include <cstddef> // size_t, ptrdiff_t
-#include <cstdint> // uint8_t
-#include <cstdio> // snprintf
-#include <limits> // numeric_limits
-#include <string> // string
-#include <type_traits> // is_same
+    /*!
+    @return The size of the BSON-encoded binary array @a value
+    */
+    static std::size_t calc_bson_binary_size(const typename BasicJsonType::binary_t& value)
+    {
+        return sizeof(std::int32_t) + value.size() + 1ul;
+    }
 
-// #include <nlohmann/detail/exceptions.hpp>
+    /*!
+    @brief Writes a BSON element with key @a name and array @a value
+    */
+    void write_bson_array(const string_t& name,
+                          const typename BasicJsonType::array_t& value)
+    {
+        write_bson_entry_header(name, 0x04); // array
+        write_number<std::int32_t, true>(static_cast<std::int32_t>(calc_bson_array_size(value)));
 
-// #include <nlohmann/detail/conversions/to_chars.hpp>
+        std::size_t array_index = 0ul;
 
+        for (const auto& el : value)
+        {
+            write_bson_element(std::to_string(array_index++), el);
+        }
 
-#include <cassert> // assert
-#include <ciso646> // or, and, not
-#include <cmath>   // signbit, isfinite
-#include <cstdint> // intN_t, uintN_t
-#include <cstring> // memcpy, memmove
+        oa->write_character(to_char_type(0x00));
+    }
 
-namespace nlohmann
-{
-namespace detail
-{
+    /*!
+    @brief Writes a BSON element with key @a name and binary value @a value
+    */
+    void write_bson_binary(const string_t& name,
+                           const binary_t& value)
+    {
+        write_bson_entry_header(name, 0x05);
 
-/*!
-@brief implements the Grisu2 algorithm for binary to decimal floating-point
-conversion.
+        write_number<std::int32_t, true>(static_cast<std::int32_t>(value.size()));
+        write_number(value.has_subtype() ? static_cast<std::uint8_t>(value.subtype()) : std::uint8_t(0x00));
 
-This implementation is a slightly modified version of the reference
-implementation which may be obtained from
-http://florian.loitsch.com/publications (bench.tar.gz).
+        oa->write_characters(reinterpret_cast<const CharType*>(value.data()), value.size());
+    }
 
-The code is distributed under the MIT license, Copyright (c) 2009 Florian Loitsch.
+    /*!
+    @brief Calculates the size necessary to serialize the JSON value @a j with its @a name
+    @return The calculated size for the BSON document entry for @a j with the given @a name.
+    */
+    static std::size_t calc_bson_element_size(const string_t& name,
+            const BasicJsonType& j)
+    {
+        const auto header_size = calc_bson_entry_header_size(name, j);
+        switch (j.type())
+        {
+            case value_t::object:
+                return header_size + calc_bson_object_size(*j.m_value.object);
 
-For a detailed description of the algorithm see:
+            case value_t::array:
+                return header_size + calc_bson_array_size(*j.m_value.array);
 
-[1] Loitsch, "Printing Floating-Point Numbers Quickly and Accurately with
-    Integers", Proceedings of the ACM SIGPLAN 2010 Conference on Programming
-    Language Design and Implementation, PLDI 2010
-[2] Burger, Dybvig, "Printing Floating-Point Numbers Quickly and Accurately",
-    Proceedings of the ACM SIGPLAN 1996 Conference on Programming Language
-    Design and Implementation, PLDI 1996
-*/
-namespace dtoa_impl
-{
+            case value_t::binary:
+                return header_size + calc_bson_binary_size(*j.m_value.binary);
 
-template <typename Target, typename Source>
-Target reinterpret_bits(const Source source)
-{
-    static_assert(sizeof(Target) == sizeof(Source), "size mismatch");
+            case value_t::boolean:
+                return header_size + 1ul;
 
-    Target target;
-    std::memcpy(&target, &source, sizeof(Source));
-    return target;
-}
+            case value_t::number_float:
+                return header_size + 8ul;
 
-struct diyfp // f * 2^e
-{
-    static constexpr int kPrecision = 64; // = q
+            case value_t::number_integer:
+                return header_size + calc_bson_integer_size(j.m_value.number_integer);
 
-    uint64_t f = 0;
-    int e = 0;
+            case value_t::number_unsigned:
+                return header_size + calc_bson_unsigned_size(j.m_value.number_unsigned);
 
-    constexpr diyfp(uint64_t f_, int e_) noexcept : f(f_), e(e_) {}
+            case value_t::string:
+                return header_size + calc_bson_string_size(*j.m_value.string);
 
-    /*!
-    @brief returns x - y
-    @pre x.e == y.e and x.f >= y.f
-    */
-    static diyfp sub(const diyfp& x, const diyfp& y) noexcept
-    {
-        assert(x.e == y.e);
-        assert(x.f >= y.f);
+            case value_t::null:
+                return header_size + 0ul;
 
-        return {x.f - y.f, x.e};
+            // LCOV_EXCL_START
+            case value_t::discarded:
+            default:
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert)
+                return 0ul;
+                // LCOV_EXCL_STOP
+        }
     }
 
     /*!
-    @brief returns x * y
-    @note The result is rounded. (Only the upper q bits are returned.)
+    @brief Serializes the JSON value @a j to BSON and associates it with the
+           key @a name.
+    @param name The name to associate with the JSON entity @a j within the
+                current BSON document
     */
-    static diyfp mul(const diyfp& x, const diyfp& y) noexcept
+    void write_bson_element(const string_t& name,
+                            const BasicJsonType& j)
     {
-        static_assert(kPrecision == 64, "internal error");
-
-        // Computes:
-        //  f = round((x.f * y.f) / 2^q)
-        //  e = x.e + y.e + q
+        switch (j.type())
+        {
+            case value_t::object:
+                return write_bson_object_entry(name, *j.m_value.object);
 
-        // Emulate the 64-bit * 64-bit multiplication:
-        //
-        // p = u * v
-        //   = (u_lo + 2^32 u_hi) (v_lo + 2^32 v_hi)
-        //   = (u_lo v_lo         ) + 2^32 ((u_lo v_hi         ) + (u_hi v_lo         )) + 2^64 (u_hi v_hi         )
-        //   = (p0                ) + 2^32 ((p1                ) + (p2                )) + 2^64 (p3                )
-        //   = (p0_lo + 2^32 p0_hi) + 2^32 ((p1_lo + 2^32 p1_hi) + (p2_lo + 2^32 p2_hi)) + 2^64 (p3                )
-        //   = (p0_lo             ) + 2^32 (p0_hi + p1_lo + p2_lo                      ) + 2^64 (p1_hi + p2_hi + p3)
-        //   = (p0_lo             ) + 2^32 (Q                                          ) + 2^64 (H                 )
-        //   = (p0_lo             ) + 2^32 (Q_lo + 2^32 Q_hi                           ) + 2^64 (H                 )
-        //
-        // (Since Q might be larger than 2^32 - 1)
-        //
-        //   = (p0_lo + 2^32 Q_lo) + 2^64 (Q_hi + H)
-        //
-        // (Q_hi + H does not overflow a 64-bit int)
-        //
-        //   = p_lo + 2^64 p_hi
+            case value_t::array:
+                return write_bson_array(name, *j.m_value.array);
 
-        const uint64_t u_lo = x.f & 0xFFFFFFFF;
-        const uint64_t u_hi = x.f >> 32;
-        const uint64_t v_lo = y.f & 0xFFFFFFFF;
-        const uint64_t v_hi = y.f >> 32;
+            case value_t::binary:
+                return write_bson_binary(name, *j.m_value.binary);
 
-        const uint64_t p0 = u_lo * v_lo;
-        const uint64_t p1 = u_lo * v_hi;
-        const uint64_t p2 = u_hi * v_lo;
-        const uint64_t p3 = u_hi * v_hi;
+            case value_t::boolean:
+                return write_bson_boolean(name, j.m_value.boolean);
 
-        const uint64_t p0_hi = p0 >> 32;
-        const uint64_t p1_lo = p1 & 0xFFFFFFFF;
-        const uint64_t p1_hi = p1 >> 32;
-        const uint64_t p2_lo = p2 & 0xFFFFFFFF;
-        const uint64_t p2_hi = p2 >> 32;
+            case value_t::number_float:
+                return write_bson_double(name, j.m_value.number_float);
 
-        uint64_t Q = p0_hi + p1_lo + p2_lo;
+            case value_t::number_integer:
+                return write_bson_integer(name, j.m_value.number_integer);
 
-        // The full product might now be computed as
-        //
-        // p_hi = p3 + p2_hi + p1_hi + (Q >> 32)
-        // p_lo = p0_lo + (Q << 32)
-        //
-        // But in this particular case here, the full p_lo is not required.
-        // Effectively we only need to add the highest bit in p_lo to p_hi (and
-        // Q_hi + 1 does not overflow).
+            case value_t::number_unsigned:
+                return write_bson_unsigned(name, j);
 
-        Q += uint64_t{1} << (64 - 32 - 1); // round, ties up
+            case value_t::string:
+                return write_bson_string(name, *j.m_value.string);
 
-        const uint64_t h = p3 + p2_hi + p1_hi + (Q >> 32);
+            case value_t::null:
+                return write_bson_null(name);
 
-        return {h, x.e + y.e + 64};
+            // LCOV_EXCL_START
+            case value_t::discarded:
+            default:
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert)
+                return;
+                // LCOV_EXCL_STOP
+        }
     }
 
     /*!
-    @brief normalize x such that the significand is >= 2^(q-1)
-    @pre x.f != 0
+    @brief Calculates the size of the BSON serialization of the given
+           JSON-object @a j.
+    @param[in] value  JSON value to serialize
+    @pre       value.type() == value_t::object
     */
-    static diyfp normalize(diyfp x) noexcept
+    static std::size_t calc_bson_object_size(const typename BasicJsonType::object_t& value)
     {
-        assert(x.f != 0);
-
-        while ((x.f >> 63) == 0)
+        std::size_t document_size = std::accumulate(value.begin(), value.end(), std::size_t(0),
+                                    [](size_t result, const typename BasicJsonType::object_t::value_type & el)
         {
-            x.f <<= 1;
-            x.e--;
-        }
+            return result += calc_bson_element_size(el.first, el.second);
+        });
 
-        return x;
+        return sizeof(std::int32_t) + document_size + 1ul;
     }
 
     /*!
-    @brief normalize x such that the result has the exponent E
-    @pre e >= x.e and the upper e - x.e bits of x.f must be zero.
+    @param[in] value  JSON value to serialize
+    @pre       value.type() == value_t::object
     */
-    static diyfp normalize_to(const diyfp& x, const int target_exponent) noexcept
+    void write_bson_object(const typename BasicJsonType::object_t& value)
     {
-        const int delta = x.e - target_exponent;
+        write_number<std::int32_t, true>(static_cast<std::int32_t>(calc_bson_object_size(value)));
 
-        assert(delta >= 0);
-        assert(((x.f << delta) >> delta) == x.f);
+        for (const auto& el : value)
+        {
+            write_bson_element(el.first, el.second);
+        }
 
-        return {x.f << delta, target_exponent};
+        oa->write_character(to_char_type(0x00));
     }
-};
-
-struct boundaries
-{
-    diyfp w;
-    diyfp minus;
-    diyfp plus;
-};
-
-/*!
-Compute the (normalized) diyfp representing the input number 'value' and its
-boundaries.
-
-@pre value must be finite and positive
-*/
-template <typename FloatType>
-boundaries compute_boundaries(FloatType value)
-{
-    assert(std::isfinite(value));
-    assert(value > 0);
-
-    // Convert the IEEE representation into a diyfp.
-    //
-    // If v is denormal:
-    //      value = 0.F * 2^(1 - bias) = (          F) * 2^(1 - bias - (p-1))
-    // If v is normalized:
-    //      value = 1.F * 2^(E - bias) = (2^(p-1) + F) * 2^(E - bias - (p-1))
-
-    static_assert(std::numeric_limits<FloatType>::is_iec559,
-                  "internal error: dtoa_short requires an IEEE-754 floating-point implementation");
 
-    constexpr int      kPrecision = std::numeric_limits<FloatType>::digits; // = p (includes the hidden bit)
-    constexpr int      kBias      = std::numeric_limits<FloatType>::max_exponent - 1 + (kPrecision - 1);
-    constexpr int      kMinExp    = 1 - kBias;
-    constexpr uint64_t kHiddenBit = uint64_t{1} << (kPrecision - 1); // = 2^(p-1)
-
-    using bits_type = typename std::conditional< kPrecision == 24, uint32_t, uint64_t >::type;
+    //////////
+    // CBOR //
+    //////////
 
-    const uint64_t bits = reinterpret_bits<bits_type>(value);
-    const uint64_t E = bits >> (kPrecision - 1);
-    const uint64_t F = bits & (kHiddenBit - 1);
+    static constexpr CharType get_cbor_float_prefix(float /*unused*/)
+    {
+        return to_char_type(0xFA);  // Single-Precision Float
+    }
 
-    const bool is_denormal = (E == 0);
-    const diyfp v = is_denormal
-                    ? diyfp(F, kMinExp)
-                    : diyfp(F + kHiddenBit, static_cast<int>(E) - kBias);
+    static constexpr CharType get_cbor_float_prefix(double /*unused*/)
+    {
+        return to_char_type(0xFB);  // Double-Precision Float
+    }
 
-    // Compute the boundaries m- and m+ of the floating-point value
-    // v = f * 2^e.
-    //
-    // Determine v- and v+, the floating-point predecessor and successor if v,
-    // respectively.
-    //
-    //      v- = v - 2^e        if f != 2^(p-1) or e == e_min                (A)
-    //         = v - 2^(e-1)    if f == 2^(p-1) and e > e_min                (B)
-    //
-    //      v+ = v + 2^e
-    //
-    // Let m- = (v- + v) / 2 and m+ = (v + v+) / 2. All real numbers _strictly_
-    // between m- and m+ round to v, regardless of how the input rounding
-    // algorithm breaks ties.
-    //
-    //      ---+-------------+-------------+-------------+-------------+---  (A)
-    //         v-            m-            v             m+            v+
-    //
-    //      -----------------+------+------+-------------+-------------+---  (B)
-    //                       v-     m-     v             m+            v+
+    /////////////
+    // MsgPack //
+    /////////////
 
-    const bool lower_boundary_is_closer = (F == 0 and E > 1);
-    const diyfp m_plus = diyfp(2 * v.f + 1, v.e - 1);
-    const diyfp m_minus = lower_boundary_is_closer
-                          ? diyfp(4 * v.f - 1, v.e - 2)  // (B)
-                          : diyfp(2 * v.f - 1, v.e - 1); // (A)
+    static constexpr CharType get_msgpack_float_prefix(float /*unused*/)
+    {
+        return to_char_type(0xCA);  // float 32
+    }
 
-    // Determine the normalized w+ = m+.
-    const diyfp w_plus = diyfp::normalize(m_plus);
+    static constexpr CharType get_msgpack_float_prefix(double /*unused*/)
+    {
+        return to_char_type(0xCB);  // float 64
+    }
 
-    // Determine w- = m- such that e_(w-) = e_(w+).
-    const diyfp w_minus = diyfp::normalize_to(m_minus, w_plus.e);
+    ////////////
+    // UBJSON //
+    ////////////
 
-    return {diyfp::normalize(v), w_minus, w_plus};
-}
+    // UBJSON: write number (floating point)
+    template<typename NumberType, typename std::enable_if<
+                 std::is_floating_point<NumberType>::value, int>::type = 0>
+    void write_number_with_ubjson_prefix(const NumberType n,
+                                         const bool add_prefix)
+    {
+        if (add_prefix)
+        {
+            oa->write_character(get_ubjson_float_prefix(n));
+        }
+        write_number(n);
+    }
 
-// Given normalized diyfp w, Grisu needs to find a (normalized) cached
-// power-of-ten c, such that the exponent of the product c * w = f * 2^e lies
-// within a certain range [alpha, gamma] (Definition 3.2 from [1])
-//
-//      alpha <= e = e_c + e_w + q <= gamma
-//
-// or
-//
-//      f_c * f_w * 2^alpha <= f_c 2^(e_c) * f_w 2^(e_w) * 2^q
-//                          <= f_c * f_w * 2^gamma
-//
-// Since c and w are normalized, i.e. 2^(q-1) <= f < 2^q, this implies
-//
-//      2^(q-1) * 2^(q-1) * 2^alpha <= c * w * 2^q < 2^q * 2^q * 2^gamma
-//
-// or
-//
-//      2^(q - 2 + alpha) <= c * w < 2^(q + gamma)
-//
-// The choice of (alpha,gamma) determines the size of the table and the form of
-// the digit generation procedure. Using (alpha,gamma)=(-60,-32) works out well
-// in practice:
-//
-// The idea is to cut the number c * w = f * 2^e into two parts, which can be
-// processed independently: An integral part p1, and a fractional part p2:
-//
-//      f * 2^e = ( (f div 2^-e) * 2^-e + (f mod 2^-e) ) * 2^e
-//              = (f div 2^-e) + (f mod 2^-e) * 2^e
-//              = p1 + p2 * 2^e
-//
-// The conversion of p1 into decimal form requires a series of divisions and
-// modulos by (a power of) 10. These operations are faster for 32-bit than for
-// 64-bit integers, so p1 should ideally fit into a 32-bit integer. This can be
-// achieved by choosing
-//
-//      -e >= 32   or   e <= -32 := gamma
-//
-// In order to convert the fractional part
-//
-//      p2 * 2^e = p2 / 2^-e = d[-1] / 10^1 + d[-2] / 10^2 + ...
-//
-// into decimal form, the fraction is repeatedly multiplied by 10 and the digits
-// d[-i] are extracted in order:
-//
-//      (10 * p2) div 2^-e = d[-1]
-//      (10 * p2) mod 2^-e = d[-2] / 10^1 + ...
-//
-// The multiplication by 10 must not overflow. It is sufficient to choose
-//
-//      10 * p2 < 16 * p2 = 2^4 * p2 <= 2^64.
-//
-// Since p2 = f mod 2^-e < 2^-e,
-//
-//      -e <= 60   or   e >= -60 := alpha
+    // UBJSON: write number (unsigned integer)
+    template<typename NumberType, typename std::enable_if<
+                 std::is_unsigned<NumberType>::value, int>::type = 0>
+    void write_number_with_ubjson_prefix(const NumberType n,
+                                         const bool add_prefix)
+    {
+        if (n <= static_cast<std::uint64_t>((std::numeric_limits<std::int8_t>::max)()))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('i'));  // int8
+            }
+            write_number(static_cast<std::uint8_t>(n));
+        }
+        else if (n <= (std::numeric_limits<std::uint8_t>::max)())
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('U'));  // uint8
+            }
+            write_number(static_cast<std::uint8_t>(n));
+        }
+        else if (n <= static_cast<std::uint64_t>((std::numeric_limits<std::int16_t>::max)()))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('I'));  // int16
+            }
+            write_number(static_cast<std::int16_t>(n));
+        }
+        else if (n <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('l'));  // int32
+            }
+            write_number(static_cast<std::int32_t>(n));
+        }
+        else if (n <= static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('L'));  // int64
+            }
+            write_number(static_cast<std::int64_t>(n));
+        }
+        else
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('H'));  // high-precision number
+            }
 
-constexpr int kAlpha = -60;
-constexpr int kGamma = -32;
+            const auto number = BasicJsonType(n).dump();
+            write_number_with_ubjson_prefix(number.size(), true);
+            for (std::size_t i = 0; i < number.size(); ++i)
+            {
+                oa->write_character(to_char_type(static_cast<std::uint8_t>(number[i])));
+            }
+        }
+    }
 
-struct cached_power // c = f * 2^e ~= 10^k
-{
-    uint64_t f;
-    int e;
-    int k;
-};
+    // UBJSON: write number (signed integer)
+    template < typename NumberType, typename std::enable_if <
+                   std::is_signed<NumberType>::value&&
+                   !std::is_floating_point<NumberType>::value, int >::type = 0 >
+    void write_number_with_ubjson_prefix(const NumberType n,
+                                         const bool add_prefix)
+    {
+        if ((std::numeric_limits<std::int8_t>::min)() <= n && n <= (std::numeric_limits<std::int8_t>::max)())
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('i'));  // int8
+            }
+            write_number(static_cast<std::int8_t>(n));
+        }
+        else if (static_cast<std::int64_t>((std::numeric_limits<std::uint8_t>::min)()) <= n && n <= static_cast<std::int64_t>((std::numeric_limits<std::uint8_t>::max)()))
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('U'));  // uint8
+            }
+            write_number(static_cast<std::uint8_t>(n));
+        }
+        else if ((std::numeric_limits<std::int16_t>::min)() <= n && n <= (std::numeric_limits<std::int16_t>::max)())
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('I'));  // int16
+            }
+            write_number(static_cast<std::int16_t>(n));
+        }
+        else if ((std::numeric_limits<std::int32_t>::min)() <= n && n <= (std::numeric_limits<std::int32_t>::max)())
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('l'));  // int32
+            }
+            write_number(static_cast<std::int32_t>(n));
+        }
+        else if ((std::numeric_limits<std::int64_t>::min)() <= n && n <= (std::numeric_limits<std::int64_t>::max)())
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('L'));  // int64
+            }
+            write_number(static_cast<std::int64_t>(n));
+        }
+        // LCOV_EXCL_START
+        else
+        {
+            if (add_prefix)
+            {
+                oa->write_character(to_char_type('H'));  // high-precision number
+            }
 
-/*!
-For a normalized diyfp w = f * 2^e, this function returns a (normalized) cached
-power-of-ten c = f_c * 2^e_c, such that the exponent of the product w * c
-satisfies (Definition 3.2 from [1])
+            const auto number = BasicJsonType(n).dump();
+            write_number_with_ubjson_prefix(number.size(), true);
+            for (std::size_t i = 0; i < number.size(); ++i)
+            {
+                oa->write_character(to_char_type(static_cast<std::uint8_t>(number[i])));
+            }
+        }
+        // LCOV_EXCL_STOP
+    }
 
-     alpha <= e_c + e + q <= gamma.
-*/
-inline cached_power get_cached_power_for_binary_exponent(int e)
-{
-    // Now
-    //
-    //      alpha <= e_c + e + q <= gamma                                    (1)
-    //      ==> f_c * 2^alpha <= c * 2^e * 2^q
-    //
-    // and since the c's are normalized, 2^(q-1) <= f_c,
-    //
-    //      ==> 2^(q - 1 + alpha) <= c * 2^(e + q)
-    //      ==> 2^(alpha - e - 1) <= c
-    //
-    // If c were an exakt power of ten, i.e. c = 10^k, one may determine k as
-    //
-    //      k = ceil( log_10( 2^(alpha - e - 1) ) )
-    //        = ceil( (alpha - e - 1) * log_10(2) )
-    //
-    // From the paper:
-    // "In theory the result of the procedure could be wrong since c is rounded,
-    //  and the computation itself is approximated [...]. In practice, however,
-    //  this simple function is sufficient."
-    //
-    // For IEEE double precision floating-point numbers converted into
-    // normalized diyfp's w = f * 2^e, with q = 64,
-    //
-    //      e >= -1022      (min IEEE exponent)
-    //           -52        (p - 1)
-    //           -52        (p - 1, possibly normalize denormal IEEE numbers)
-    //           -11        (normalize the diyfp)
-    //         = -1137
-    //
-    // and
-    //
-    //      e <= +1023      (max IEEE exponent)
-    //           -52        (p - 1)
-    //           -11        (normalize the diyfp)
-    //         = 960
-    //
-    // This binary exponent range [-1137,960] results in a decimal exponent
-    // range [-307,324]. One does not need to store a cached power for each
-    // k in this range. For each such k it suffices to find a cached power
-    // such that the exponent of the product lies in [alpha,gamma].
-    // This implies that the difference of the decimal exponents of adjacent
-    // table entries must be less than or equal to
-    //
-    //      floor( (gamma - alpha) * log_10(2) ) = 8.
-    //
-    // (A smaller distance gamma-alpha would require a larger table.)
+    /*!
+    @brief determine the type prefix of container values
+    */
+    CharType ubjson_prefix(const BasicJsonType& j) const noexcept
+    {
+        switch (j.type())
+        {
+            case value_t::null:
+                return 'Z';
 
-    // NB:
-    // Actually this function returns c, such that -60 <= e_c + e + 64 <= -34.
+            case value_t::boolean:
+                return j.m_value.boolean ? 'T' : 'F';
 
-    constexpr int kCachedPowersSize = 79;
-    constexpr int kCachedPowersMinDecExp = -300;
-    constexpr int kCachedPowersDecStep = 8;
+            case value_t::number_integer:
+            {
+                if ((std::numeric_limits<std::int8_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::int8_t>::max)())
+                {
+                    return 'i';
+                }
+                if ((std::numeric_limits<std::uint8_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::uint8_t>::max)())
+                {
+                    return 'U';
+                }
+                if ((std::numeric_limits<std::int16_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::int16_t>::max)())
+                {
+                    return 'I';
+                }
+                if ((std::numeric_limits<std::int32_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::int32_t>::max)())
+                {
+                    return 'l';
+                }
+                if ((std::numeric_limits<std::int64_t>::min)() <= j.m_value.number_integer && j.m_value.number_integer <= (std::numeric_limits<std::int64_t>::max)())
+                {
+                    return 'L';
+                }
+                // anything else is treated as high-precision number
+                return 'H'; // LCOV_EXCL_LINE
+            }
 
-    static constexpr cached_power kCachedPowers[] =
-    {
-        { 0xAB70FE17C79AC6CA, -1060, -300 },
-        { 0xFF77B1FCBEBCDC4F, -1034, -292 },
-        { 0xBE5691EF416BD60C, -1007, -284 },
-        { 0x8DD01FAD907FFC3C,  -980, -276 },
-        { 0xD3515C2831559A83,  -954, -268 },
-        { 0x9D71AC8FADA6C9B5,  -927, -260 },
-        { 0xEA9C227723EE8BCB,  -901, -252 },
-        { 0xAECC49914078536D,  -874, -244 },
-        { 0x823C12795DB6CE57,  -847, -236 },
-        { 0xC21094364DFB5637,  -821, -228 },
-        { 0x9096EA6F3848984F,  -794, -220 },
-        { 0xD77485CB25823AC7,  -768, -212 },
-        { 0xA086CFCD97BF97F4,  -741, -204 },
-        { 0xEF340A98172AACE5,  -715, -196 },
-        { 0xB23867FB2A35B28E,  -688, -188 },
-        { 0x84C8D4DFD2C63F3B,  -661, -180 },
-        { 0xC5DD44271AD3CDBA,  -635, -172 },
-        { 0x936B9FCEBB25C996,  -608, -164 },
-        { 0xDBAC6C247D62A584,  -582, -156 },
-        { 0xA3AB66580D5FDAF6,  -555, -148 },
-        { 0xF3E2F893DEC3F126,  -529, -140 },
-        { 0xB5B5ADA8AAFF80B8,  -502, -132 },
-        { 0x87625F056C7C4A8B,  -475, -124 },
-        { 0xC9BCFF6034C13053,  -449, -116 },
-        { 0x964E858C91BA2655,  -422, -108 },
-        { 0xDFF9772470297EBD,  -396, -100 },
-        { 0xA6DFBD9FB8E5B88F,  -369,  -92 },
-        { 0xF8A95FCF88747D94,  -343,  -84 },
-        { 0xB94470938FA89BCF,  -316,  -76 },
-        { 0x8A08F0F8BF0F156B,  -289,  -68 },
-        { 0xCDB02555653131B6,  -263,  -60 },
-        { 0x993FE2C6D07B7FAC,  -236,  -52 },
-        { 0xE45C10C42A2B3B06,  -210,  -44 },
-        { 0xAA242499697392D3,  -183,  -36 },
-        { 0xFD87B5F28300CA0E,  -157,  -28 },
-        { 0xBCE5086492111AEB,  -130,  -20 },
-        { 0x8CBCCC096F5088CC,  -103,  -12 },
-        { 0xD1B71758E219652C,   -77,   -4 },
-        { 0x9C40000000000000,   -50,    4 },
-        { 0xE8D4A51000000000,   -24,   12 },
-        { 0xAD78EBC5AC620000,     3,   20 },
-        { 0x813F3978F8940984,    30,   28 },
-        { 0xC097CE7BC90715B3,    56,   36 },
-        { 0x8F7E32CE7BEA5C70,    83,   44 },
-        { 0xD5D238A4ABE98068,   109,   52 },
-        { 0x9F4F2726179A2245,   136,   60 },
-        { 0xED63A231D4C4FB27,   162,   68 },
-        { 0xB0DE65388CC8ADA8,   189,   76 },
-        { 0x83C7088E1AAB65DB,   216,   84 },
-        { 0xC45D1DF942711D9A,   242,   92 },
-        { 0x924D692CA61BE758,   269,  100 },
-        { 0xDA01EE641A708DEA,   295,  108 },
-        { 0xA26DA3999AEF774A,   322,  116 },
-        { 0xF209787BB47D6B85,   348,  124 },
-        { 0xB454E4A179DD1877,   375,  132 },
-        { 0x865B86925B9BC5C2,   402,  140 },
-        { 0xC83553C5C8965D3D,   428,  148 },
-        { 0x952AB45CFA97A0B3,   455,  156 },
-        { 0xDE469FBD99A05FE3,   481,  164 },
-        { 0xA59BC234DB398C25,   508,  172 },
-        { 0xF6C69A72A3989F5C,   534,  180 },
-        { 0xB7DCBF5354E9BECE,   561,  188 },
-        { 0x88FCF317F22241E2,   588,  196 },
-        { 0xCC20CE9BD35C78A5,   614,  204 },
-        { 0x98165AF37B2153DF,   641,  212 },
-        { 0xE2A0B5DC971F303A,   667,  220 },
-        { 0xA8D9D1535CE3B396,   694,  228 },
-        { 0xFB9B7CD9A4A7443C,   720,  236 },
-        { 0xBB764C4CA7A44410,   747,  244 },
-        { 0x8BAB8EEFB6409C1A,   774,  252 },
-        { 0xD01FEF10A657842C,   800,  260 },
-        { 0x9B10A4E5E9913129,   827,  268 },
-        { 0xE7109BFBA19C0C9D,   853,  276 },
-        { 0xAC2820D9623BF429,   880,  284 },
-        { 0x80444B5E7AA7CF85,   907,  292 },
-        { 0xBF21E44003ACDD2D,   933,  300 },
-        { 0x8E679C2F5E44FF8F,   960,  308 },
-        { 0xD433179D9C8CB841,   986,  316 },
-        { 0x9E19DB92B4E31BA9,  1013,  324 },
-    };
+            case value_t::number_unsigned:
+            {
+                if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int8_t>::max)()))
+                {
+                    return 'i';
+                }
+                if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::uint8_t>::max)()))
+                {
+                    return 'U';
+                }
+                if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int16_t>::max)()))
+                {
+                    return 'I';
+                }
+                if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int32_t>::max)()))
+                {
+                    return 'l';
+                }
+                if (j.m_value.number_unsigned <= static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()))
+                {
+                    return 'L';
+                }
+                // anything else is treated as high-precision number
+                return 'H'; // LCOV_EXCL_LINE
+            }
 
-    // This computation gives exactly the same results for k as
-    //      k = ceil((kAlpha - e - 1) * 0.30102999566398114)
-    // for |e| <= 1500, but doesn't require floating-point operations.
-    // NB: log_10(2) ~= 78913 / 2^18
-    assert(e >= -1500);
-    assert(e <=  1500);
-    const int f = kAlpha - e - 1;
-    const int k = (f * 78913) / (1 << 18) + static_cast<int>(f > 0);
+            case value_t::number_float:
+                return get_ubjson_float_prefix(j.m_value.number_float);
 
-    const int index = (-kCachedPowersMinDecExp + k + (kCachedPowersDecStep - 1)) / kCachedPowersDecStep;
-    assert(index >= 0);
-    assert(index < kCachedPowersSize);
-    static_cast<void>(kCachedPowersSize); // Fix warning.
+            case value_t::string:
+                return 'S';
 
-    const cached_power cached = kCachedPowers[index];
-    assert(kAlpha <= cached.e + e + 64);
-    assert(kGamma >= cached.e + e + 64);
+            case value_t::array: // fallthrough
+            case value_t::binary:
+                return '[';
 
-    return cached;
-}
+            case value_t::object:
+                return '{';
 
-/*!
-For n != 0, returns k, such that pow10 := 10^(k-1) <= n < 10^k.
-For n == 0, returns 1 and sets pow10 := 1.
-*/
-inline int find_largest_pow10(const uint32_t n, uint32_t& pow10)
-{
-    // LCOV_EXCL_START
-    if (n >= 1000000000)
-    {
-        pow10 = 1000000000;
-        return 10;
-    }
-    // LCOV_EXCL_STOP
-    else if (n >= 100000000)
-    {
-        pow10 = 100000000;
-        return  9;
+            case value_t::discarded:
+            default:  // discarded values
+                return 'N';
+        }
     }
-    else if (n >= 10000000)
+
+    static constexpr CharType get_ubjson_float_prefix(float /*unused*/)
     {
-        pow10 = 10000000;
-        return  8;
+        return 'd';  // float 32
     }
-    else if (n >= 1000000)
+
+    static constexpr CharType get_ubjson_float_prefix(double /*unused*/)
     {
-        pow10 = 1000000;
-        return  7;
+        return 'D';  // float 64
     }
-    else if (n >= 100000)
+
+    ///////////////////////
+    // Utility functions //
+    ///////////////////////
+
+    /*
+    @brief write a number to output input
+    @param[in] n number of type @a NumberType
+    @tparam NumberType the type of the number
+    @tparam OutputIsLittleEndian Set to true if output data is
+                                 required to be little endian
+
+    @note This function needs to respect the system's endianess, because bytes
+          in CBOR, MessagePack, and UBJSON are stored in network order (big
+          endian) and therefore need reordering on little endian systems.
+    */
+    template<typename NumberType, bool OutputIsLittleEndian = false>
+    void write_number(const NumberType n)
     {
-        pow10 = 100000;
-        return  6;
+        // step 1: write number to array of length NumberType
+        std::array<CharType, sizeof(NumberType)> vec{};
+        std::memcpy(vec.data(), &n, sizeof(NumberType));
+
+        // step 2: write array to output (with possible reordering)
+        if (is_little_endian != OutputIsLittleEndian)
+        {
+            // reverse byte order prior to conversion if necessary
+            std::reverse(vec.begin(), vec.end());
+        }
+
+        oa->write_characters(vec.data(), sizeof(NumberType));
     }
-    else if (n >= 10000)
+
+    void write_compact_float(const number_float_t n, detail::input_format_t format)
     {
-        pow10 = 10000;
-        return  5;
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+        if (static_cast<double>(n) >= static_cast<double>(std::numeric_limits<float>::lowest()) &&
+                static_cast<double>(n) <= static_cast<double>((std::numeric_limits<float>::max)()) &&
+                static_cast<double>(static_cast<float>(n)) == static_cast<double>(n))
+        {
+            oa->write_character(format == detail::input_format_t::cbor
+                                ? get_cbor_float_prefix(static_cast<float>(n))
+                                : get_msgpack_float_prefix(static_cast<float>(n)));
+            write_number(static_cast<float>(n));
+        }
+        else
+        {
+            oa->write_character(format == detail::input_format_t::cbor
+                                ? get_cbor_float_prefix(n)
+                                : get_msgpack_float_prefix(n));
+            write_number(n);
+        }
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
     }
-    else if (n >= 1000)
+
+  public:
+    // The following to_char_type functions are implement the conversion
+    // between uint8_t and CharType. In case CharType is not unsigned,
+    // such a conversion is required to allow values greater than 128.
+    // See <https://github.com/nlohmann/json/issues/1286> for a discussion.
+    template < typename C = CharType,
+               enable_if_t < std::is_signed<C>::value && std::is_signed<char>::value > * = nullptr >
+    static constexpr CharType to_char_type(std::uint8_t x) noexcept
     {
-        pow10 = 1000;
-        return  4;
+        return *reinterpret_cast<char*>(&x);
     }
-    else if (n >= 100)
+
+    template < typename C = CharType,
+               enable_if_t < std::is_signed<C>::value && std::is_unsigned<char>::value > * = nullptr >
+    static CharType to_char_type(std::uint8_t x) noexcept
     {
-        pow10 = 100;
-        return  3;
+        static_assert(sizeof(std::uint8_t) == sizeof(CharType), "size of CharType must be equal to std::uint8_t");
+        static_assert(std::is_trivial<CharType>::value, "CharType must be trivial");
+        CharType result;
+        std::memcpy(&result, &x, sizeof(x));
+        return result;
     }
-    else if (n >= 10)
+
+    template<typename C = CharType,
+             enable_if_t<std::is_unsigned<C>::value>* = nullptr>
+    static constexpr CharType to_char_type(std::uint8_t x) noexcept
     {
-        pow10 = 10;
-        return  2;
+        return x;
     }
-    else
+
+    template < typename InputCharType, typename C = CharType,
+               enable_if_t <
+                   std::is_signed<C>::value &&
+                   std::is_signed<char>::value &&
+                   std::is_same<char, typename std::remove_cv<InputCharType>::type>::value
+                   > * = nullptr >
+    static constexpr CharType to_char_type(InputCharType x) noexcept
     {
-        pow10 = 1;
-        return 1;
+        return x;
     }
-}
 
-inline void grisu2_round(char* buf, int len, uint64_t dist, uint64_t delta,
-                         uint64_t rest, uint64_t ten_k)
-{
-    assert(len >= 1);
-    assert(dist <= delta);
-    assert(rest <= delta);
-    assert(ten_k > 0);
+  private:
+    /// whether we can assume little endianess
+    const bool is_little_endian = little_endianess();
 
-    //               <--------------------------- delta ---->
-    //                                  <---- dist --------->
-    // --------------[------------------+-------------------]--------------
-    //               M-                 w                   M+
-    //
-    //                                  ten_k
-    //                                <------>
-    //                                       <---- rest ---->
-    // --------------[------------------+----+--------------]--------------
-    //                                  w    V
-    //                                       = buf * 10^k
-    //
-    // ten_k represents a unit-in-the-last-place in the decimal representation
-    // stored in buf.
-    // Decrement buf by ten_k while this takes buf closer to w.
+    /// the output
+    output_adapter_t<CharType> oa = nullptr;
+};
+}  // namespace detail
+}  // namespace nlohmann
 
-    // The tests are written in this order to avoid overflow in unsigned
-    // integer arithmetic.
+// #include <nlohmann/detail/output/output_adapters.hpp>
 
-    while (rest < dist
-            and delta - rest >= ten_k
-            and (rest + ten_k < dist or dist - rest > rest + ten_k - dist))
-    {
-        assert(buf[len - 1] != '0');
-        buf[len - 1]--;
-        rest += ten_k;
-    }
-}
+// #include <nlohmann/detail/output/serializer.hpp>
 
-/*!
-Generates V = buffer * 10^decimal_exponent, such that M- <= V <= M+.
-M- and M+ must be normalized and share the same exponent -60 <= e <= -32.
-*/
-inline void grisu2_digit_gen(char* buffer, int& length, int& decimal_exponent,
-                             diyfp M_minus, diyfp w, diyfp M_plus)
-{
-    static_assert(kAlpha >= -60, "internal error");
-    static_assert(kGamma <= -32, "internal error");
 
-    // Generates the digits (and the exponent) of a decimal floating-point
-    // number V = buffer * 10^decimal_exponent in the range [M-, M+]. The diyfp's
-    // w, M- and M+ share the same exponent e, which satisfies alpha <= e <= gamma.
-    //
-    //               <--------------------------- delta ---->
-    //                                  <---- dist --------->
-    // --------------[------------------+-------------------]--------------
-    //               M-                 w                   M+
-    //
-    // Grisu2 generates the digits of M+ from left to right and stops as soon as
-    // V is in [M-,M+].
+#include <algorithm> // reverse, remove, fill, find, none_of
+#include <array> // array
+#include <clocale> // localeconv, lconv
+#include <cmath> // labs, isfinite, isnan, signbit
+#include <cstddef> // size_t, ptrdiff_t
+#include <cstdint> // uint8_t
+#include <cstdio> // snprintf
+#include <limits> // numeric_limits
+#include <string> // string, char_traits
+#include <type_traits> // is_same
+#include <utility> // move
 
-    assert(M_plus.e >= kAlpha);
-    assert(M_plus.e <= kGamma);
+// #include <nlohmann/detail/conversions/to_chars.hpp>
 
-    uint64_t delta = diyfp::sub(M_plus, M_minus).f; // (significand of (M+ - M-), implicit exponent is e)
-    uint64_t dist  = diyfp::sub(M_plus, w      ).f; // (significand of (M+ - w ), implicit exponent is e)
 
-    // Split M+ = f * 2^e into two parts p1 and p2 (note: e < 0):
-    //
-    //      M+ = f * 2^e
-    //         = ((f div 2^-e) * 2^-e + (f mod 2^-e)) * 2^e
-    //         = ((p1        ) * 2^-e + (p2        )) * 2^e
-    //         = p1 + p2 * 2^e
+#include <array> // array
+#include <cmath>   // signbit, isfinite
+#include <cstdint> // intN_t, uintN_t
+#include <cstring> // memcpy, memmove
+#include <limits> // numeric_limits
+#include <type_traits> // conditional
 
-    const diyfp one(uint64_t{1} << -M_plus.e, M_plus.e);
+// #include <nlohmann/detail/macro_scope.hpp>
 
-    auto p1 = static_cast<uint32_t>(M_plus.f >> -one.e); // p1 = f div 2^-e (Since -e >= 32, p1 fits into a 32-bit int.)
-    uint64_t p2 = M_plus.f & (one.f - 1);                    // p2 = f mod 2^-e
 
-    // 1)
-    //
-    // Generate the digits of the integral part p1 = d[n-1]...d[1]d[0]
+namespace nlohmann
+{
+namespace detail
+{
 
-    assert(p1 > 0);
+/*!
+@brief implements the Grisu2 algorithm for binary to decimal floating-point
+conversion.
 
-    uint32_t pow10;
-    const int k = find_largest_pow10(p1, pow10);
+This implementation is a slightly modified version of the reference
+implementation which may be obtained from
+http://florian.loitsch.com/publications (bench.tar.gz).
 
-    //      10^(k-1) <= p1 < 10^k, pow10 = 10^(k-1)
-    //
-    //      p1 = (p1 div 10^(k-1)) * 10^(k-1) + (p1 mod 10^(k-1))
-    //         = (d[k-1]         ) * 10^(k-1) + (p1 mod 10^(k-1))
-    //
-    //      M+ = p1                                             + p2 * 2^e
-    //         = d[k-1] * 10^(k-1) + (p1 mod 10^(k-1))          + p2 * 2^e
-    //         = d[k-1] * 10^(k-1) + ((p1 mod 10^(k-1)) * 2^-e + p2) * 2^e
-    //         = d[k-1] * 10^(k-1) + (                         rest) * 2^e
-    //
-    // Now generate the digits d[n] of p1 from left to right (n = k-1,...,0)
-    //
-    //      p1 = d[k-1]...d[n] * 10^n + d[n-1]...d[0]
-    //
-    // but stop as soon as
-    //
-    //      rest * 2^e = (d[n-1]...d[0] * 2^-e + p2) * 2^e <= delta * 2^e
+The code is distributed under the MIT license, Copyright (c) 2009 Florian Loitsch.
 
-    int n = k;
-    while (n > 0)
-    {
-        // Invariants:
-        //      M+ = buffer * 10^n + (p1 + p2 * 2^e)    (buffer = 0 for n = k)
-        //      pow10 = 10^(n-1) <= p1 < 10^n
-        //
-        const uint32_t d = p1 / pow10;  // d = p1 div 10^(n-1)
-        const uint32_t r = p1 % pow10;  // r = p1 mod 10^(n-1)
-        //
-        //      M+ = buffer * 10^n + (d * 10^(n-1) + r) + p2 * 2^e
-        //         = (buffer * 10 + d) * 10^(n-1) + (r + p2 * 2^e)
-        //
-        assert(d <= 9);
-        buffer[length++] = static_cast<char>('0' + d); // buffer := buffer * 10 + d
-        //
-        //      M+ = buffer * 10^(n-1) + (r + p2 * 2^e)
-        //
-        p1 = r;
-        n--;
-        //
-        //      M+ = buffer * 10^n + (p1 + p2 * 2^e)
-        //      pow10 = 10^n
-        //
+For a detailed description of the algorithm see:
 
-        // Now check if enough digits have been generated.
-        // Compute
-        //
-        //      p1 + p2 * 2^e = (p1 * 2^-e + p2) * 2^e = rest * 2^e
-        //
-        // Note:
-        // Since rest and delta share the same exponent e, it suffices to
-        // compare the significands.
-        const uint64_t rest = (uint64_t{p1} << -one.e) + p2;
-        if (rest <= delta)
-        {
-            // V = buffer * 10^n, with M- <= V <= M+.
+[1] Loitsch, "Printing Floating-Point Numbers Quickly and Accurately with
+    Integers", Proceedings of the ACM SIGPLAN 2010 Conference on Programming
+    Language Design and Implementation, PLDI 2010
+[2] Burger, Dybvig, "Printing Floating-Point Numbers Quickly and Accurately",
+    Proceedings of the ACM SIGPLAN 1996 Conference on Programming Language
+    Design and Implementation, PLDI 1996
+*/
+namespace dtoa_impl
+{
 
-            decimal_exponent += n;
+template<typename Target, typename Source>
+Target reinterpret_bits(const Source source)
+{
+    static_assert(sizeof(Target) == sizeof(Source), "size mismatch");
 
-            // We may now just stop. But instead look if the buffer could be
-            // decremented to bring V closer to w.
-            //
-            // pow10 = 10^n is now 1 ulp in the decimal representation V.
-            // The rounding procedure works with diyfp's with an implicit
-            // exponent of e.
-            //
-            //      10^n = (10^n * 2^-e) * 2^e = ulp * 2^e
-            //
-            const uint64_t ten_n = uint64_t{pow10} << -one.e;
-            grisu2_round(buffer, length, dist, delta, rest, ten_n);
+    Target target;
+    std::memcpy(&target, &source, sizeof(Source));
+    return target;
+}
 
-            return;
-        }
+struct diyfp // f * 2^e
+{
+    static constexpr int kPrecision = 64; // = q
 
-        pow10 /= 10;
-        //
-        //      pow10 = 10^(n-1) <= p1 < 10^n
-        // Invariants restored.
-    }
+    std::uint64_t f = 0;
+    int e = 0;
 
-    // 2)
-    //
-    // The digits of the integral part have been generated:
-    //
-    //      M+ = d[k-1]...d[1]d[0] + p2 * 2^e
-    //         = buffer            + p2 * 2^e
-    //
-    // Now generate the digits of the fractional part p2 * 2^e.
-    //
-    // Note:
-    // No decimal point is generated: the exponent is adjusted instead.
-    //
-    // p2 actually represents the fraction
-    //
-    //      p2 * 2^e
-    //          = p2 / 2^-e
-    //          = d[-1] / 10^1 + d[-2] / 10^2 + ...
-    //
-    // Now generate the digits d[-m] of p1 from left to right (m = 1,2,...)
-    //
-    //      p2 * 2^e = d[-1]d[-2]...d[-m] * 10^-m
-    //                      + 10^-m * (d[-m-1] / 10^1 + d[-m-2] / 10^2 + ...)
-    //
-    // using
-    //
-    //      10^m * p2 = ((10^m * p2) div 2^-e) * 2^-e + ((10^m * p2) mod 2^-e)
-    //                = (                   d) * 2^-e + (                   r)
-    //
-    // or
-    //      10^m * p2 * 2^e = d + r * 2^e
-    //
-    // i.e.
-    //
-    //      M+ = buffer + p2 * 2^e
-    //         = buffer + 10^-m * (d + r * 2^e)
-    //         = (buffer * 10^m + d) * 10^-m + 10^-m * r * 2^e
-    //
-    // and stop as soon as 10^-m * r * 2^e <= delta * 2^e
+    constexpr diyfp(std::uint64_t f_, int e_) noexcept : f(f_), e(e_) {}
+
+    /*!
+    @brief returns x - y
+    @pre x.e == y.e and x.f >= y.f
+    */
+    static diyfp sub(const diyfp& x, const diyfp& y) noexcept
+    {
+        JSON_ASSERT(x.e == y.e);
+        JSON_ASSERT(x.f >= y.f);
 
-    assert(p2 > delta);
+        return {x.f - y.f, x.e};
+    }
 
-    int m = 0;
-    for (;;)
+    /*!
+    @brief returns x * y
+    @note The result is rounded. (Only the upper q bits are returned.)
+    */
+    static diyfp mul(const diyfp& x, const diyfp& y) noexcept
     {
-        // Invariant:
-        //      M+ = buffer * 10^-m + 10^-m * (d[-m-1] / 10 + d[-m-2] / 10^2 + ...) * 2^e
-        //         = buffer * 10^-m + 10^-m * (p2                                 ) * 2^e
-        //         = buffer * 10^-m + 10^-m * (1/10 * (10 * p2)                   ) * 2^e
-        //         = buffer * 10^-m + 10^-m * (1/10 * ((10*p2 div 2^-e) * 2^-e + (10*p2 mod 2^-e)) * 2^e
-        //
-        assert(p2 <= UINT64_MAX / 10);
-        p2 *= 10;
-        const uint64_t d = p2 >> -one.e;     // d = (10 * p2) div 2^-e
-        const uint64_t r = p2 & (one.f - 1); // r = (10 * p2) mod 2^-e
+        static_assert(kPrecision == 64, "internal error");
+
+        // Computes:
+        //  f = round((x.f * y.f) / 2^q)
+        //  e = x.e + y.e + q
+
+        // Emulate the 64-bit * 64-bit multiplication:
         //
-        //      M+ = buffer * 10^-m + 10^-m * (1/10 * (d * 2^-e + r) * 2^e
-        //         = buffer * 10^-m + 10^-m * (1/10 * (d + r * 2^e))
-        //         = (buffer * 10 + d) * 10^(-m-1) + 10^(-m-1) * r * 2^e
+        // p = u * v
+        //   = (u_lo + 2^32 u_hi) (v_lo + 2^32 v_hi)
+        //   = (u_lo v_lo         ) + 2^32 ((u_lo v_hi         ) + (u_hi v_lo         )) + 2^64 (u_hi v_hi         )
+        //   = (p0                ) + 2^32 ((p1                ) + (p2                )) + 2^64 (p3                )
+        //   = (p0_lo + 2^32 p0_hi) + 2^32 ((p1_lo + 2^32 p1_hi) + (p2_lo + 2^32 p2_hi)) + 2^64 (p3                )
+        //   = (p0_lo             ) + 2^32 (p0_hi + p1_lo + p2_lo                      ) + 2^64 (p1_hi + p2_hi + p3)
+        //   = (p0_lo             ) + 2^32 (Q                                          ) + 2^64 (H                 )
+        //   = (p0_lo             ) + 2^32 (Q_lo + 2^32 Q_hi                           ) + 2^64 (H                 )
         //
-        assert(d <= 9);
-        buffer[length++] = static_cast<char>('0' + d); // buffer := buffer * 10 + d
+        // (Since Q might be larger than 2^32 - 1)
         //
-        //      M+ = buffer * 10^(-m-1) + 10^(-m-1) * r * 2^e
+        //   = (p0_lo + 2^32 Q_lo) + 2^64 (Q_hi + H)
         //
-        p2 = r;
-        m++;
+        // (Q_hi + H does not overflow a 64-bit int)
         //
-        //      M+ = buffer * 10^-m + 10^-m * p2 * 2^e
-        // Invariant restored.
+        //   = p_lo + 2^64 p_hi
 
-        // Check if enough digits have been generated.
+        const std::uint64_t u_lo = x.f & 0xFFFFFFFFu;
+        const std::uint64_t u_hi = x.f >> 32u;
+        const std::uint64_t v_lo = y.f & 0xFFFFFFFFu;
+        const std::uint64_t v_hi = y.f >> 32u;
+
+        const std::uint64_t p0 = u_lo * v_lo;
+        const std::uint64_t p1 = u_lo * v_hi;
+        const std::uint64_t p2 = u_hi * v_lo;
+        const std::uint64_t p3 = u_hi * v_hi;
+
+        const std::uint64_t p0_hi = p0 >> 32u;
+        const std::uint64_t p1_lo = p1 & 0xFFFFFFFFu;
+        const std::uint64_t p1_hi = p1 >> 32u;
+        const std::uint64_t p2_lo = p2 & 0xFFFFFFFFu;
+        const std::uint64_t p2_hi = p2 >> 32u;
+
+        std::uint64_t Q = p0_hi + p1_lo + p2_lo;
+
+        // The full product might now be computed as
+        //
+        // p_hi = p3 + p2_hi + p1_hi + (Q >> 32)
+        // p_lo = p0_lo + (Q << 32)
         //
-        //      10^-m * p2 * 2^e <= delta * 2^e
-        //              p2 * 2^e <= 10^m * delta * 2^e
-        //                    p2 <= 10^m * delta
-        delta *= 10;
-        dist  *= 10;
-        if (p2 <= delta)
+        // But in this particular case here, the full p_lo is not required.
+        // Effectively we only need to add the highest bit in p_lo to p_hi (and
+        // Q_hi + 1 does not overflow).
+
+        Q += std::uint64_t{1} << (64u - 32u - 1u); // round, ties up
+
+        const std::uint64_t h = p3 + p2_hi + p1_hi + (Q >> 32u);
+
+        return {h, x.e + y.e + 64};
+    }
+
+    /*!
+    @brief normalize x such that the significand is >= 2^(q-1)
+    @pre x.f != 0
+    */
+    static diyfp normalize(diyfp x) noexcept
+    {
+        JSON_ASSERT(x.f != 0);
+
+        while ((x.f >> 63u) == 0)
         {
-            break;
+            x.f <<= 1u;
+            x.e--;
         }
+
+        return x;
     }
 
-    // V = buffer * 10^-m, with M- <= V <= M+.
+    /*!
+    @brief normalize x such that the result has the exponent E
+    @pre e >= x.e and the upper e - x.e bits of x.f must be zero.
+    */
+    static diyfp normalize_to(const diyfp& x, const int target_exponent) noexcept
+    {
+        const int delta = x.e - target_exponent;
 
-    decimal_exponent -= m;
+        JSON_ASSERT(delta >= 0);
+        JSON_ASSERT(((x.f << delta) >> delta) == x.f);
 
-    // 1 ulp in the decimal representation is now 10^-m.
-    // Since delta and dist are now scaled by 10^m, we need to do the
-    // same with ulp in order to keep the units in sync.
-    //
-    //      10^m * 10^-m = 1 = 2^-e * 2^e = ten_m * 2^e
-    //
-    const uint64_t ten_m = one.f;
-    grisu2_round(buffer, length, dist, delta, p2, ten_m);
+        return {x.f << delta, target_exponent};
+    }
+};
 
-    // By construction this algorithm generates the shortest possible decimal
-    // number (Loitsch, Theorem 6.2) which rounds back to w.
-    // For an input number of precision p, at least
-    //
-    //      N = 1 + ceil(p * log_10(2))
-    //
-    // decimal digits are sufficient to identify all binary floating-point
-    // numbers (Matula, "In-and-Out conversions").
-    // This implies that the algorithm does not produce more than N decimal
-    // digits.
-    //
-    //      N = 17 for p = 53 (IEEE double precision)
-    //      N = 9  for p = 24 (IEEE single precision)
-}
+struct boundaries
+{
+    diyfp w;
+    diyfp minus;
+    diyfp plus;
+};
 
 /*!
-v = buf * 10^decimal_exponent
-len is the length of the buffer (number of decimal digits)
-The buffer must be large enough, i.e. >= max_digits10.
+Compute the (normalized) diyfp representing the input number 'value' and its
+boundaries.
+
+@pre value must be finite and positive
 */
-inline void grisu2(char* buf, int& len, int& decimal_exponent,
-                   diyfp m_minus, diyfp v, diyfp m_plus)
+template<typename FloatType>
+boundaries compute_boundaries(FloatType value)
 {
-    assert(m_plus.e == m_minus.e);
-    assert(m_plus.e == v.e);
+    JSON_ASSERT(std::isfinite(value));
+    JSON_ASSERT(value > 0);
 
-    //  --------(-----------------------+-----------------------)--------    (A)
-    //          m-                      v                       m+
-    //
-    //  --------------------(-----------+-----------------------)--------    (B)
-    //                      m-          v                       m+
+    // Convert the IEEE representation into a diyfp.
     //
-    // First scale v (and m- and m+) such that the exponent is in the range
-    // [alpha, gamma].
+    // If v is denormal:
+    //      value = 0.F * 2^(1 - bias) = (          F) * 2^(1 - bias - (p-1))
+    // If v is normalized:
+    //      value = 1.F * 2^(E - bias) = (2^(p-1) + F) * 2^(E - bias - (p-1))
 
-    const cached_power cached = get_cached_power_for_binary_exponent(m_plus.e);
+    static_assert(std::numeric_limits<FloatType>::is_iec559,
+                  "internal error: dtoa_short requires an IEEE-754 floating-point implementation");
 
-    const diyfp c_minus_k(cached.f, cached.e); // = c ~= 10^-k
+    constexpr int      kPrecision = std::numeric_limits<FloatType>::digits; // = p (includes the hidden bit)
+    constexpr int      kBias      = std::numeric_limits<FloatType>::max_exponent - 1 + (kPrecision - 1);
+    constexpr int      kMinExp    = 1 - kBias;
+    constexpr std::uint64_t kHiddenBit = std::uint64_t{1} << (kPrecision - 1); // = 2^(p-1)
 
-    // The exponent of the products is = v.e + c_minus_k.e + q and is in the range [alpha,gamma]
-    const diyfp w       = diyfp::mul(v,       c_minus_k);
-    const diyfp w_minus = diyfp::mul(m_minus, c_minus_k);
-    const diyfp w_plus  = diyfp::mul(m_plus,  c_minus_k);
+    using bits_type = typename std::conditional<kPrecision == 24, std::uint32_t, std::uint64_t >::type;
 
-    //  ----(---+---)---------------(---+---)---------------(---+---)----
-    //          w-                      w                       w+
-    //          = c*m-                  = c*v                   = c*m+
+    const auto bits = static_cast<std::uint64_t>(reinterpret_bits<bits_type>(value));
+    const std::uint64_t E = bits >> (kPrecision - 1);
+    const std::uint64_t F = bits & (kHiddenBit - 1);
+
+    const bool is_denormal = E == 0;
+    const diyfp v = is_denormal
+                    ? diyfp(F, kMinExp)
+                    : diyfp(F + kHiddenBit, static_cast<int>(E) - kBias);
+
+    // Compute the boundaries m- and m+ of the floating-point value
+    // v = f * 2^e.
     //
-    // diyfp::mul rounds its result and c_minus_k is approximated too. w, w- and
-    // w+ are now off by a small amount.
-    // In fact:
+    // Determine v- and v+, the floating-point predecessor and successor if v,
+    // respectively.
     //
-    //      w - v * 10^k < 1 ulp
+    //      v- = v - 2^e        if f != 2^(p-1) or e == e_min                (A)
+    //         = v - 2^(e-1)    if f == 2^(p-1) and e > e_min                (B)
     //
-    // To account for this inaccuracy, add resp. subtract 1 ulp.
+    //      v+ = v + 2^e
     //
-    //  --------+---[---------------(---+---)---------------]---+--------
-    //          w-  M-                  w                   M+  w+
+    // Let m- = (v- + v) / 2 and m+ = (v + v+) / 2. All real numbers _strictly_
+    // between m- and m+ round to v, regardless of how the input rounding
+    // algorithm breaks ties.
     //
-    // Now any number in [M-, M+] (bounds included) will round to w when input,
-    // regardless of how the input rounding algorithm breaks ties.
+    //      ---+-------------+-------------+-------------+-------------+---  (A)
+    //         v-            m-            v             m+            v+
     //
-    // And digit_gen generates the shortest possible such number in [M-, M+].
-    // Note that this does not mean that Grisu2 always generates the shortest
-    // possible number in the interval (m-, m+).
-    const diyfp M_minus(w_minus.f + 1, w_minus.e);
-    const diyfp M_plus (w_plus.f  - 1, w_plus.e );
-
-    decimal_exponent = -cached.k; // = -(-k) = k
-
-    grisu2_digit_gen(buf, len, decimal_exponent, M_minus, w, M_plus);
-}
+    //      -----------------+------+------+-------------+-------------+---  (B)
+    //                       v-     m-     v             m+            v+
 
-/*!
-v = buf * 10^decimal_exponent
-len is the length of the buffer (number of decimal digits)
-The buffer must be large enough, i.e. >= max_digits10.
-*/
-template <typename FloatType>
-void grisu2(char* buf, int& len, int& decimal_exponent, FloatType value)
-{
-    static_assert(diyfp::kPrecision >= std::numeric_limits<FloatType>::digits + 3,
-                  "internal error: not enough precision");
+    const bool lower_boundary_is_closer = F == 0 && E > 1;
+    const diyfp m_plus = diyfp(2 * v.f + 1, v.e - 1);
+    const diyfp m_minus = lower_boundary_is_closer
+                          ? diyfp(4 * v.f - 1, v.e - 2)  // (B)
+                          : diyfp(2 * v.f - 1, v.e - 1); // (A)
 
-    assert(std::isfinite(value));
-    assert(value > 0);
+    // Determine the normalized w+ = m+.
+    const diyfp w_plus = diyfp::normalize(m_plus);
 
-    // If the neighbors (and boundaries) of 'value' are always computed for double-precision
-    // numbers, all float's can be recovered using strtod (and strtof). However, the resulting
-    // decimal representations are not exactly "short".
-    //
-    // The documentation for 'std::to_chars' (https://en.cppreference.com/w/cpp/utility/to_chars)
-    // says "value is converted to a string as if by std::sprintf in the default ("C") locale"
-    // and since sprintf promotes float's to double's, I think this is exactly what 'std::to_chars'
-    // does.
-    // On the other hand, the documentation for 'std::to_chars' requires that "parsing the
-    // representation using the corresponding std::from_chars function recovers value exactly". That
-    // indicates that single precision floating-point numbers should be recovered using
-    // 'std::strtof'.
-    //
-    // NB: If the neighbors are computed for single-precision numbers, there is a single float
-    //     (7.0385307e-26f) which can't be recovered using strtod. The resulting double precision
-    //     value is off by 1 ulp.
-#if 0
-    const boundaries w = compute_boundaries(static_cast<double>(value));
-#else
-    const boundaries w = compute_boundaries(value);
-#endif
+    // Determine w- = m- such that e_(w-) = e_(w+).
+    const diyfp w_minus = diyfp::normalize_to(m_minus, w_plus.e);
 
-    grisu2(buf, len, decimal_exponent, w.minus, w.w, w.plus);
+    return {diyfp::normalize(v), w_minus, w_plus};
 }
 
-/*!
-@brief appends a decimal representation of e to buf
-@return a pointer to the element following the exponent.
-@pre -1000 < e < 1000
-*/
-inline char* append_exponent(char* buf, int e)
-{
-    assert(e > -1000);
-    assert(e <  1000);
-
-    if (e < 0)
-    {
-        e = -e;
-        *buf++ = '-';
-    }
-    else
-    {
-        *buf++ = '+';
-    }
-
-    auto k = static_cast<uint32_t>(e);
-    if (k < 10)
-    {
-        // Always print at least two digits in the exponent.
-        // This is for compatibility with printf("%g").
-        *buf++ = '0';
-        *buf++ = static_cast<char>('0' + k);
-    }
-    else if (k < 100)
-    {
-        *buf++ = static_cast<char>('0' + k / 10);
-        k %= 10;
-        *buf++ = static_cast<char>('0' + k);
-    }
-    else
-    {
-        *buf++ = static_cast<char>('0' + k / 100);
-        k %= 100;
-        *buf++ = static_cast<char>('0' + k / 10);
-        k %= 10;
-        *buf++ = static_cast<char>('0' + k);
-    }
+// Given normalized diyfp w, Grisu needs to find a (normalized) cached
+// power-of-ten c, such that the exponent of the product c * w = f * 2^e lies
+// within a certain range [alpha, gamma] (Definition 3.2 from [1])
+//
+//      alpha <= e = e_c + e_w + q <= gamma
+//
+// or
+//
+//      f_c * f_w * 2^alpha <= f_c 2^(e_c) * f_w 2^(e_w) * 2^q
+//                          <= f_c * f_w * 2^gamma
+//
+// Since c and w are normalized, i.e. 2^(q-1) <= f < 2^q, this implies
+//
+//      2^(q-1) * 2^(q-1) * 2^alpha <= c * w * 2^q < 2^q * 2^q * 2^gamma
+//
+// or
+//
+//      2^(q - 2 + alpha) <= c * w < 2^(q + gamma)
+//
+// The choice of (alpha,gamma) determines the size of the table and the form of
+// the digit generation procedure. Using (alpha,gamma)=(-60,-32) works out well
+// in practice:
+//
+// The idea is to cut the number c * w = f * 2^e into two parts, which can be
+// processed independently: An integral part p1, and a fractional part p2:
+//
+//      f * 2^e = ( (f div 2^-e) * 2^-e + (f mod 2^-e) ) * 2^e
+//              = (f div 2^-e) + (f mod 2^-e) * 2^e
+//              = p1 + p2 * 2^e
+//
+// The conversion of p1 into decimal form requires a series of divisions and
+// modulos by (a power of) 10. These operations are faster for 32-bit than for
+// 64-bit integers, so p1 should ideally fit into a 32-bit integer. This can be
+// achieved by choosing
+//
+//      -e >= 32   or   e <= -32 := gamma
+//
+// In order to convert the fractional part
+//
+//      p2 * 2^e = p2 / 2^-e = d[-1] / 10^1 + d[-2] / 10^2 + ...
+//
+// into decimal form, the fraction is repeatedly multiplied by 10 and the digits
+// d[-i] are extracted in order:
+//
+//      (10 * p2) div 2^-e = d[-1]
+//      (10 * p2) mod 2^-e = d[-2] / 10^1 + ...
+//
+// The multiplication by 10 must not overflow. It is sufficient to choose
+//
+//      10 * p2 < 16 * p2 = 2^4 * p2 <= 2^64.
+//
+// Since p2 = f mod 2^-e < 2^-e,
+//
+//      -e <= 60   or   e >= -60 := alpha
 
-    return buf;
-}
+constexpr int kAlpha = -60;
+constexpr int kGamma = -32;
 
-/*!
-@brief prettify v = buf * 10^decimal_exponent
+struct cached_power // c = f * 2^e ~= 10^k
+{
+    std::uint64_t f;
+    int e;
+    int k;
+};
 
-If v is in the range [10^min_exp, 10^max_exp) it will be printed in fixed-point
-notation. Otherwise it will be printed in exponential notation.
+/*!
+For a normalized diyfp w = f * 2^e, this function returns a (normalized) cached
+power-of-ten c = f_c * 2^e_c, such that the exponent of the product w * c
+satisfies (Definition 3.2 from [1])
 
-@pre min_exp < 0
-@pre max_exp > 0
+     alpha <= e_c + e + q <= gamma.
 */
-inline char* format_buffer(char* buf, int len, int decimal_exponent,
-                           int min_exp, int max_exp)
+inline cached_power get_cached_power_for_binary_exponent(int e)
 {
-    assert(min_exp < 0);
-    assert(max_exp > 0);
+    // Now
+    //
+    //      alpha <= e_c + e + q <= gamma                                    (1)
+    //      ==> f_c * 2^alpha <= c * 2^e * 2^q
+    //
+    // and since the c's are normalized, 2^(q-1) <= f_c,
+    //
+    //      ==> 2^(q - 1 + alpha) <= c * 2^(e + q)
+    //      ==> 2^(alpha - e - 1) <= c
+    //
+    // If c were an exact power of ten, i.e. c = 10^k, one may determine k as
+    //
+    //      k = ceil( log_10( 2^(alpha - e - 1) ) )
+    //        = ceil( (alpha - e - 1) * log_10(2) )
+    //
+    // From the paper:
+    // "In theory the result of the procedure could be wrong since c is rounded,
+    //  and the computation itself is approximated [...]. In practice, however,
+    //  this simple function is sufficient."
+    //
+    // For IEEE double precision floating-point numbers converted into
+    // normalized diyfp's w = f * 2^e, with q = 64,
+    //
+    //      e >= -1022      (min IEEE exponent)
+    //           -52        (p - 1)
+    //           -52        (p - 1, possibly normalize denormal IEEE numbers)
+    //           -11        (normalize the diyfp)
+    //         = -1137
+    //
+    // and
+    //
+    //      e <= +1023      (max IEEE exponent)
+    //           -52        (p - 1)
+    //           -11        (normalize the diyfp)
+    //         = 960
+    //
+    // This binary exponent range [-1137,960] results in a decimal exponent
+    // range [-307,324]. One does not need to store a cached power for each
+    // k in this range. For each such k it suffices to find a cached power
+    // such that the exponent of the product lies in [alpha,gamma].
+    // This implies that the difference of the decimal exponents of adjacent
+    // table entries must be less than or equal to
+    //
+    //      floor( (gamma - alpha) * log_10(2) ) = 8.
+    //
+    // (A smaller distance gamma-alpha would require a larger table.)
 
-    const int k = len;
-    const int n = len + decimal_exponent;
+    // NB:
+    // Actually this function returns c, such that -60 <= e_c + e + 64 <= -34.
 
-    // v = buf * 10^(n-k)
-    // k is the length of the buffer (number of decimal digits)
-    // n is the position of the decimal point relative to the start of the buffer.
+    constexpr int kCachedPowersMinDecExp = -300;
+    constexpr int kCachedPowersDecStep = 8;
 
-    if (k <= n and n <= max_exp)
-    {
-        // digits[000]
-        // len <= max_exp + 2
+    static constexpr std::array<cached_power, 79> kCachedPowers =
+    {
+        {
+            { 0xAB70FE17C79AC6CA, -1060, -300 },
+            { 0xFF77B1FCBEBCDC4F, -1034, -292 },
+            { 0xBE5691EF416BD60C, -1007, -284 },
+            { 0x8DD01FAD907FFC3C,  -980, -276 },
+            { 0xD3515C2831559A83,  -954, -268 },
+            { 0x9D71AC8FADA6C9B5,  -927, -260 },
+            { 0xEA9C227723EE8BCB,  -901, -252 },
+            { 0xAECC49914078536D,  -874, -244 },
+            { 0x823C12795DB6CE57,  -847, -236 },
+            { 0xC21094364DFB5637,  -821, -228 },
+            { 0x9096EA6F3848984F,  -794, -220 },
+            { 0xD77485CB25823AC7,  -768, -212 },
+            { 0xA086CFCD97BF97F4,  -741, -204 },
+            { 0xEF340A98172AACE5,  -715, -196 },
+            { 0xB23867FB2A35B28E,  -688, -188 },
+            { 0x84C8D4DFD2C63F3B,  -661, -180 },
+            { 0xC5DD44271AD3CDBA,  -635, -172 },
+            { 0x936B9FCEBB25C996,  -608, -164 },
+            { 0xDBAC6C247D62A584,  -582, -156 },
+            { 0xA3AB66580D5FDAF6,  -555, -148 },
+            { 0xF3E2F893DEC3F126,  -529, -140 },
+            { 0xB5B5ADA8AAFF80B8,  -502, -132 },
+            { 0x87625F056C7C4A8B,  -475, -124 },
+            { 0xC9BCFF6034C13053,  -449, -116 },
+            { 0x964E858C91BA2655,  -422, -108 },
+            { 0xDFF9772470297EBD,  -396, -100 },
+            { 0xA6DFBD9FB8E5B88F,  -369,  -92 },
+            { 0xF8A95FCF88747D94,  -343,  -84 },
+            { 0xB94470938FA89BCF,  -316,  -76 },
+            { 0x8A08F0F8BF0F156B,  -289,  -68 },
+            { 0xCDB02555653131B6,  -263,  -60 },
+            { 0x993FE2C6D07B7FAC,  -236,  -52 },
+            { 0xE45C10C42A2B3B06,  -210,  -44 },
+            { 0xAA242499697392D3,  -183,  -36 },
+            { 0xFD87B5F28300CA0E,  -157,  -28 },
+            { 0xBCE5086492111AEB,  -130,  -20 },
+            { 0x8CBCCC096F5088CC,  -103,  -12 },
+            { 0xD1B71758E219652C,   -77,   -4 },
+            { 0x9C40000000000000,   -50,    4 },
+            { 0xE8D4A51000000000,   -24,   12 },
+            { 0xAD78EBC5AC620000,     3,   20 },
+            { 0x813F3978F8940984,    30,   28 },
+            { 0xC097CE7BC90715B3,    56,   36 },
+            { 0x8F7E32CE7BEA5C70,    83,   44 },
+            { 0xD5D238A4ABE98068,   109,   52 },
+            { 0x9F4F2726179A2245,   136,   60 },
+            { 0xED63A231D4C4FB27,   162,   68 },
+            { 0xB0DE65388CC8ADA8,   189,   76 },
+            { 0x83C7088E1AAB65DB,   216,   84 },
+            { 0xC45D1DF942711D9A,   242,   92 },
+            { 0x924D692CA61BE758,   269,  100 },
+            { 0xDA01EE641A708DEA,   295,  108 },
+            { 0xA26DA3999AEF774A,   322,  116 },
+            { 0xF209787BB47D6B85,   348,  124 },
+            { 0xB454E4A179DD1877,   375,  132 },
+            { 0x865B86925B9BC5C2,   402,  140 },
+            { 0xC83553C5C8965D3D,   428,  148 },
+            { 0x952AB45CFA97A0B3,   455,  156 },
+            { 0xDE469FBD99A05FE3,   481,  164 },
+            { 0xA59BC234DB398C25,   508,  172 },
+            { 0xF6C69A72A3989F5C,   534,  180 },
+            { 0xB7DCBF5354E9BECE,   561,  188 },
+            { 0x88FCF317F22241E2,   588,  196 },
+            { 0xCC20CE9BD35C78A5,   614,  204 },
+            { 0x98165AF37B2153DF,   641,  212 },
+            { 0xE2A0B5DC971F303A,   667,  220 },
+            { 0xA8D9D1535CE3B396,   694,  228 },
+            { 0xFB9B7CD9A4A7443C,   720,  236 },
+            { 0xBB764C4CA7A44410,   747,  244 },
+            { 0x8BAB8EEFB6409C1A,   774,  252 },
+            { 0xD01FEF10A657842C,   800,  260 },
+            { 0x9B10A4E5E9913129,   827,  268 },
+            { 0xE7109BFBA19C0C9D,   853,  276 },
+            { 0xAC2820D9623BF429,   880,  284 },
+            { 0x80444B5E7AA7CF85,   907,  292 },
+            { 0xBF21E44003ACDD2D,   933,  300 },
+            { 0x8E679C2F5E44FF8F,   960,  308 },
+            { 0xD433179D9C8CB841,   986,  316 },
+            { 0x9E19DB92B4E31BA9,  1013,  324 },
+        }
+    };
 
-        std::memset(buf + k, '0', static_cast<size_t>(n - k));
-        // Make it look like a floating-point number (#362, #378)
-        buf[n + 0] = '.';
-        buf[n + 1] = '0';
-        return buf + (n + 2);
-    }
+    // This computation gives exactly the same results for k as
+    //      k = ceil((kAlpha - e - 1) * 0.30102999566398114)
+    // for |e| <= 1500, but doesn't require floating-point operations.
+    // NB: log_10(2) ~= 78913 / 2^18
+    JSON_ASSERT(e >= -1500);
+    JSON_ASSERT(e <=  1500);
+    const int f = kAlpha - e - 1;
+    const int k = (f * 78913) / (1 << 18) + static_cast<int>(f > 0);
 
-    if (0 < n and n <= max_exp)
-    {
-        // dig.its
-        // len <= max_digits10 + 1
+    const int index = (-kCachedPowersMinDecExp + k + (kCachedPowersDecStep - 1)) / kCachedPowersDecStep;
+    JSON_ASSERT(index >= 0);
+    JSON_ASSERT(static_cast<std::size_t>(index) < kCachedPowers.size());
 
-        assert(k > n);
+    const cached_power cached = kCachedPowers[static_cast<std::size_t>(index)];
+    JSON_ASSERT(kAlpha <= cached.e + e + 64);
+    JSON_ASSERT(kGamma >= cached.e + e + 64);
 
-        std::memmove(buf + (n + 1), buf + n, static_cast<size_t>(k - n));
-        buf[n] = '.';
-        return buf + (k + 1);
-    }
+    return cached;
+}
 
-    if (min_exp < n and n <= 0)
+/*!
+For n != 0, returns k, such that pow10 := 10^(k-1) <= n < 10^k.
+For n == 0, returns 1 and sets pow10 := 1.
+*/
+inline int find_largest_pow10(const std::uint32_t n, std::uint32_t& pow10)
+{
+    // LCOV_EXCL_START
+    if (n >= 1000000000)
     {
-        // 0.[000]digits
-        // len <= 2 + (-min_exp - 1) + max_digits10
-
-        std::memmove(buf + (2 + -n), buf, static_cast<size_t>(k));
-        buf[0] = '0';
-        buf[1] = '.';
-        std::memset(buf + 2, '0', static_cast<size_t>(-n));
-        return buf + (2 + (-n) + k);
+        pow10 = 1000000000;
+        return 10;
     }
-
-    if (k == 1)
+    // LCOV_EXCL_STOP
+    if (n >= 100000000)
     {
-        // dE+123
-        // len <= 1 + 5
-
-        buf += 1;
+        pow10 = 100000000;
+        return  9;
     }
-    else
+    if (n >= 10000000)
     {
-        // d.igitsE+123
-        // len <= max_digits10 + 1 + 5
-
-        std::memmove(buf + 2, buf + 1, static_cast<size_t>(k - 1));
-        buf[1] = '.';
-        buf += 1 + k;
+        pow10 = 10000000;
+        return  8;
     }
-
-    *buf++ = 'e';
-    return append_exponent(buf, n - 1);
-}
-
-} // namespace dtoa_impl
-
-/*!
-@brief generates a decimal representation of the floating-point number value in [first, last).
-
-The format of the resulting decimal representation is similar to printf's %g
-format. Returns an iterator pointing past-the-end of the decimal representation.
-
-@note The input number must be finite, i.e. NaN's and Inf's are not supported.
-@note The buffer must be large enough.
-@note The result is NOT null-terminated.
-*/
-template <typename FloatType>
-char* to_chars(char* first, const char* last, FloatType value)
-{
-    static_cast<void>(last); // maybe unused - fix warning
-    assert(std::isfinite(value));
-
-    // Use signbit(value) instead of (value < 0) since signbit works for -0.
-    if (std::signbit(value))
+    if (n >= 1000000)
     {
-        value = -value;
-        *first++ = '-';
+        pow10 = 1000000;
+        return  7;
     }
-
-    if (value == 0) // +-0
+    if (n >= 100000)
     {
-        *first++ = '0';
-        // Make it look like a floating-point number (#362, #378)
-        *first++ = '.';
-        *first++ = '0';
-        return first;
-    }
-
-    assert(last - first >= std::numeric_limits<FloatType>::max_digits10);
-
-    // Compute v = buffer * 10^decimal_exponent.
-    // The decimal digits are stored in the buffer, which needs to be interpreted
-    // as an unsigned decimal integer.
-    // len is the length of the buffer, i.e. the number of decimal digits.
-    int len = 0;
-    int decimal_exponent = 0;
-    dtoa_impl::grisu2(first, len, decimal_exponent, value);
-
-    assert(len <= std::numeric_limits<FloatType>::max_digits10);
-
-    // Format the buffer like printf("%.*g", prec, value)
-    constexpr int kMinExp = -4;
-    // Use digits10 here to increase compatibility with version 2.
-    constexpr int kMaxExp = std::numeric_limits<FloatType>::digits10;
-
-    assert(last - first >= kMaxExp + 2);
-    assert(last - first >= 2 + (-kMinExp - 1) + std::numeric_limits<FloatType>::max_digits10);
-    assert(last - first >= std::numeric_limits<FloatType>::max_digits10 + 6);
-
-    return dtoa_impl::format_buffer(first, len, decimal_exponent, kMinExp, kMaxExp);
-}
-
-} // namespace detail
-} // namespace nlohmann
-
-// #include <nlohmann/detail/macro_scope.hpp>
-
-// #include <nlohmann/detail/meta/cpp_future.hpp>
-
-// #include <nlohmann/detail/output/binary_writer.hpp>
-
-// #include <nlohmann/detail/output/output_adapters.hpp>
-
-// #include <nlohmann/detail/value_t.hpp>
-
-
-namespace nlohmann
-{
-namespace detail
-{
-///////////////////
-// serialization //
-///////////////////
-
-/// how to treat decoding errors
-enum class error_handler_t
-{
-    strict,  ///< throw a type_error exception in case of invalid UTF-8
-    replace, ///< replace invalid UTF-8 sequences with U+FFFD
-    ignore   ///< ignore invalid UTF-8 sequences
-};
-
-template<typename BasicJsonType>
-class serializer
-{
-    using string_t = typename BasicJsonType::string_t;
-    using number_float_t = typename BasicJsonType::number_float_t;
-    using number_integer_t = typename BasicJsonType::number_integer_t;
-    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-    static constexpr uint8_t UTF8_ACCEPT = 0;
-    static constexpr uint8_t UTF8_REJECT = 1;
-
-  public:
-    /*!
-    @param[in] s  output stream to serialize to
-    @param[in] ichar  indentation character to use
-    @param[in] error_handler_  how to react on decoding errors
-    */
-    serializer(output_adapter_t<char> s, const char ichar,
-               error_handler_t error_handler_ = error_handler_t::strict)
-        : o(std::move(s))
-        , loc(std::localeconv())
-        , thousands_sep(loc->thousands_sep == nullptr ? '\0' : * (loc->thousands_sep))
-        , decimal_point(loc->decimal_point == nullptr ? '\0' : * (loc->decimal_point))
-        , indent_char(ichar)
-        , indent_string(512, indent_char)
-        , error_handler(error_handler_)
-    {}
+        pow10 = 100000;
+        return  6;
+    }
+    if (n >= 10000)
+    {
+        pow10 = 10000;
+        return  5;
+    }
+    if (n >= 1000)
+    {
+        pow10 = 1000;
+        return  4;
+    }
+    if (n >= 100)
+    {
+        pow10 = 100;
+        return  3;
+    }
+    if (n >= 10)
+    {
+        pow10 = 10;
+        return  2;
+    }
 
-    // delete because of pointer members
-    serializer(const serializer&) = delete;
-    serializer& operator=(const serializer&) = delete;
-    serializer(serializer&&) = delete;
-    serializer& operator=(serializer&&) = delete;
-    ~serializer() = default;
+    pow10 = 1;
+    return 1;
+}
 
-    /*!
-    @brief internal implementation of the serialization function
+inline void grisu2_round(char* buf, int len, std::uint64_t dist, std::uint64_t delta,
+                         std::uint64_t rest, std::uint64_t ten_k)
+{
+    JSON_ASSERT(len >= 1);
+    JSON_ASSERT(dist <= delta);
+    JSON_ASSERT(rest <= delta);
+    JSON_ASSERT(ten_k > 0);
 
-    This function is called by the public member function dump and organizes
-    the serialization internally. The indentation level is propagated as
-    additional parameter. In case of arrays and objects, the function is
-    called recursively.
+    //               <--------------------------- delta ---->
+    //                                  <---- dist --------->
+    // --------------[------------------+-------------------]--------------
+    //               M-                 w                   M+
+    //
+    //                                  ten_k
+    //                                <------>
+    //                                       <---- rest ---->
+    // --------------[------------------+----+--------------]--------------
+    //                                  w    V
+    //                                       = buf * 10^k
+    //
+    // ten_k represents a unit-in-the-last-place in the decimal representation
+    // stored in buf.
+    // Decrement buf by ten_k while this takes buf closer to w.
 
-    - strings and object keys are escaped using `escape_string()`
-    - integer numbers are converted implicitly via `operator<<`
-    - floating-point numbers are converted to a string using `"%g"` format
+    // The tests are written in this order to avoid overflow in unsigned
+    // integer arithmetic.
 
-    @param[in] val             value to serialize
-    @param[in] pretty_print    whether the output shall be pretty-printed
-    @param[in] indent_step     the indent level
-    @param[in] current_indent  the current indent level (only used internally)
-    */
-    void dump(const BasicJsonType& val, const bool pretty_print,
-              const bool ensure_ascii,
-              const unsigned int indent_step,
-              const unsigned int current_indent = 0)
+    while (rest < dist
+            && delta - rest >= ten_k
+            && (rest + ten_k < dist || dist - rest > rest + ten_k - dist))
     {
-        switch (val.m_type)
-        {
-            case value_t::object:
-            {
-                if (val.m_value.object->empty())
-                {
-                    o->write_characters("{}", 2);
-                    return;
-                }
+        JSON_ASSERT(buf[len - 1] != '0');
+        buf[len - 1]--;
+        rest += ten_k;
+    }
+}
 
-                if (pretty_print)
-                {
-                    o->write_characters("{\n", 2);
+/*!
+Generates V = buffer * 10^decimal_exponent, such that M- <= V <= M+.
+M- and M+ must be normalized and share the same exponent -60 <= e <= -32.
+*/
+inline void grisu2_digit_gen(char* buffer, int& length, int& decimal_exponent,
+                             diyfp M_minus, diyfp w, diyfp M_plus)
+{
+    static_assert(kAlpha >= -60, "internal error");
+    static_assert(kGamma <= -32, "internal error");
 
-                    // variable to hold indentation for recursive calls
-                    const auto new_indent = current_indent + indent_step;
-                    if (JSON_UNLIKELY(indent_string.size() < new_indent))
-                    {
-                        indent_string.resize(indent_string.size() * 2, ' ');
-                    }
+    // Generates the digits (and the exponent) of a decimal floating-point
+    // number V = buffer * 10^decimal_exponent in the range [M-, M+]. The diyfp's
+    // w, M- and M+ share the same exponent e, which satisfies alpha <= e <= gamma.
+    //
+    //               <--------------------------- delta ---->
+    //                                  <---- dist --------->
+    // --------------[------------------+-------------------]--------------
+    //               M-                 w                   M+
+    //
+    // Grisu2 generates the digits of M+ from left to right and stops as soon as
+    // V is in [M-,M+].
 
-                    // first n-1 elements
-                    auto i = val.m_value.object->cbegin();
-                    for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
-                    {
-                        o->write_characters(indent_string.c_str(), new_indent);
-                        o->write_character('\"');
-                        dump_escaped(i->first, ensure_ascii);
-                        o->write_characters("\": ", 3);
-                        dump(i->second, true, ensure_ascii, indent_step, new_indent);
-                        o->write_characters(",\n", 2);
-                    }
+    JSON_ASSERT(M_plus.e >= kAlpha);
+    JSON_ASSERT(M_plus.e <= kGamma);
 
-                    // last element
-                    assert(i != val.m_value.object->cend());
-                    assert(std::next(i) == val.m_value.object->cend());
-                    o->write_characters(indent_string.c_str(), new_indent);
-                    o->write_character('\"');
-                    dump_escaped(i->first, ensure_ascii);
-                    o->write_characters("\": ", 3);
-                    dump(i->second, true, ensure_ascii, indent_step, new_indent);
+    std::uint64_t delta = diyfp::sub(M_plus, M_minus).f; // (significand of (M+ - M-), implicit exponent is e)
+    std::uint64_t dist  = diyfp::sub(M_plus, w      ).f; // (significand of (M+ - w ), implicit exponent is e)
 
-                    o->write_character('\n');
-                    o->write_characters(indent_string.c_str(), current_indent);
-                    o->write_character('}');
-                }
-                else
-                {
-                    o->write_character('{');
+    // Split M+ = f * 2^e into two parts p1 and p2 (note: e < 0):
+    //
+    //      M+ = f * 2^e
+    //         = ((f div 2^-e) * 2^-e + (f mod 2^-e)) * 2^e
+    //         = ((p1        ) * 2^-e + (p2        )) * 2^e
+    //         = p1 + p2 * 2^e
 
-                    // first n-1 elements
-                    auto i = val.m_value.object->cbegin();
-                    for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
-                    {
-                        o->write_character('\"');
-                        dump_escaped(i->first, ensure_ascii);
-                        o->write_characters("\":", 2);
-                        dump(i->second, false, ensure_ascii, indent_step, current_indent);
-                        o->write_character(',');
-                    }
+    const diyfp one(std::uint64_t{1} << -M_plus.e, M_plus.e);
 
-                    // last element
-                    assert(i != val.m_value.object->cend());
-                    assert(std::next(i) == val.m_value.object->cend());
-                    o->write_character('\"');
-                    dump_escaped(i->first, ensure_ascii);
-                    o->write_characters("\":", 2);
-                    dump(i->second, false, ensure_ascii, indent_step, current_indent);
+    auto p1 = static_cast<std::uint32_t>(M_plus.f >> -one.e); // p1 = f div 2^-e (Since -e >= 32, p1 fits into a 32-bit int.)
+    std::uint64_t p2 = M_plus.f & (one.f - 1);                    // p2 = f mod 2^-e
 
-                    o->write_character('}');
-                }
+    // 1)
+    //
+    // Generate the digits of the integral part p1 = d[n-1]...d[1]d[0]
 
-                return;
-            }
+    JSON_ASSERT(p1 > 0);
 
-            case value_t::array:
-            {
-                if (val.m_value.array->empty())
-                {
-                    o->write_characters("[]", 2);
-                    return;
-                }
+    std::uint32_t pow10{};
+    const int k = find_largest_pow10(p1, pow10);
 
-                if (pretty_print)
-                {
-                    o->write_characters("[\n", 2);
+    //      10^(k-1) <= p1 < 10^k, pow10 = 10^(k-1)
+    //
+    //      p1 = (p1 div 10^(k-1)) * 10^(k-1) + (p1 mod 10^(k-1))
+    //         = (d[k-1]         ) * 10^(k-1) + (p1 mod 10^(k-1))
+    //
+    //      M+ = p1                                             + p2 * 2^e
+    //         = d[k-1] * 10^(k-1) + (p1 mod 10^(k-1))          + p2 * 2^e
+    //         = d[k-1] * 10^(k-1) + ((p1 mod 10^(k-1)) * 2^-e + p2) * 2^e
+    //         = d[k-1] * 10^(k-1) + (                         rest) * 2^e
+    //
+    // Now generate the digits d[n] of p1 from left to right (n = k-1,...,0)
+    //
+    //      p1 = d[k-1]...d[n] * 10^n + d[n-1]...d[0]
+    //
+    // but stop as soon as
+    //
+    //      rest * 2^e = (d[n-1]...d[0] * 2^-e + p2) * 2^e <= delta * 2^e
 
-                    // variable to hold indentation for recursive calls
-                    const auto new_indent = current_indent + indent_step;
-                    if (JSON_UNLIKELY(indent_string.size() < new_indent))
-                    {
-                        indent_string.resize(indent_string.size() * 2, ' ');
-                    }
+    int n = k;
+    while (n > 0)
+    {
+        // Invariants:
+        //      M+ = buffer * 10^n + (p1 + p2 * 2^e)    (buffer = 0 for n = k)
+        //      pow10 = 10^(n-1) <= p1 < 10^n
+        //
+        const std::uint32_t d = p1 / pow10;  // d = p1 div 10^(n-1)
+        const std::uint32_t r = p1 % pow10;  // r = p1 mod 10^(n-1)
+        //
+        //      M+ = buffer * 10^n + (d * 10^(n-1) + r) + p2 * 2^e
+        //         = (buffer * 10 + d) * 10^(n-1) + (r + p2 * 2^e)
+        //
+        JSON_ASSERT(d <= 9);
+        buffer[length++] = static_cast<char>('0' + d); // buffer := buffer * 10 + d
+        //
+        //      M+ = buffer * 10^(n-1) + (r + p2 * 2^e)
+        //
+        p1 = r;
+        n--;
+        //
+        //      M+ = buffer * 10^n + (p1 + p2 * 2^e)
+        //      pow10 = 10^n
+        //
 
-                    // first n-1 elements
-                    for (auto i = val.m_value.array->cbegin();
-                            i != val.m_value.array->cend() - 1; ++i)
-                    {
-                        o->write_characters(indent_string.c_str(), new_indent);
-                        dump(*i, true, ensure_ascii, indent_step, new_indent);
-                        o->write_characters(",\n", 2);
-                    }
+        // Now check if enough digits have been generated.
+        // Compute
+        //
+        //      p1 + p2 * 2^e = (p1 * 2^-e + p2) * 2^e = rest * 2^e
+        //
+        // Note:
+        // Since rest and delta share the same exponent e, it suffices to
+        // compare the significands.
+        const std::uint64_t rest = (std::uint64_t{p1} << -one.e) + p2;
+        if (rest <= delta)
+        {
+            // V = buffer * 10^n, with M- <= V <= M+.
 
-                    // last element
-                    assert(not val.m_value.array->empty());
-                    o->write_characters(indent_string.c_str(), new_indent);
-                    dump(val.m_value.array->back(), true, ensure_ascii, indent_step, new_indent);
+            decimal_exponent += n;
 
-                    o->write_character('\n');
-                    o->write_characters(indent_string.c_str(), current_indent);
-                    o->write_character(']');
-                }
-                else
-                {
-                    o->write_character('[');
+            // We may now just stop. But instead look if the buffer could be
+            // decremented to bring V closer to w.
+            //
+            // pow10 = 10^n is now 1 ulp in the decimal representation V.
+            // The rounding procedure works with diyfp's with an implicit
+            // exponent of e.
+            //
+            //      10^n = (10^n * 2^-e) * 2^e = ulp * 2^e
+            //
+            const std::uint64_t ten_n = std::uint64_t{pow10} << -one.e;
+            grisu2_round(buffer, length, dist, delta, rest, ten_n);
 
-                    // first n-1 elements
-                    for (auto i = val.m_value.array->cbegin();
-                            i != val.m_value.array->cend() - 1; ++i)
-                    {
-                        dump(*i, false, ensure_ascii, indent_step, current_indent);
-                        o->write_character(',');
-                    }
+            return;
+        }
+
+        pow10 /= 10;
+        //
+        //      pow10 = 10^(n-1) <= p1 < 10^n
+        // Invariants restored.
+    }
 
-                    // last element
-                    assert(not val.m_value.array->empty());
-                    dump(val.m_value.array->back(), false, ensure_ascii, indent_step, current_indent);
+    // 2)
+    //
+    // The digits of the integral part have been generated:
+    //
+    //      M+ = d[k-1]...d[1]d[0] + p2 * 2^e
+    //         = buffer            + p2 * 2^e
+    //
+    // Now generate the digits of the fractional part p2 * 2^e.
+    //
+    // Note:
+    // No decimal point is generated: the exponent is adjusted instead.
+    //
+    // p2 actually represents the fraction
+    //
+    //      p2 * 2^e
+    //          = p2 / 2^-e
+    //          = d[-1] / 10^1 + d[-2] / 10^2 + ...
+    //
+    // Now generate the digits d[-m] of p1 from left to right (m = 1,2,...)
+    //
+    //      p2 * 2^e = d[-1]d[-2]...d[-m] * 10^-m
+    //                      + 10^-m * (d[-m-1] / 10^1 + d[-m-2] / 10^2 + ...)
+    //
+    // using
+    //
+    //      10^m * p2 = ((10^m * p2) div 2^-e) * 2^-e + ((10^m * p2) mod 2^-e)
+    //                = (                   d) * 2^-e + (                   r)
+    //
+    // or
+    //      10^m * p2 * 2^e = d + r * 2^e
+    //
+    // i.e.
+    //
+    //      M+ = buffer + p2 * 2^e
+    //         = buffer + 10^-m * (d + r * 2^e)
+    //         = (buffer * 10^m + d) * 10^-m + 10^-m * r * 2^e
+    //
+    // and stop as soon as 10^-m * r * 2^e <= delta * 2^e
 
-                    o->write_character(']');
-                }
+    JSON_ASSERT(p2 > delta);
 
-                return;
-            }
+    int m = 0;
+    for (;;)
+    {
+        // Invariant:
+        //      M+ = buffer * 10^-m + 10^-m * (d[-m-1] / 10 + d[-m-2] / 10^2 + ...) * 2^e
+        //         = buffer * 10^-m + 10^-m * (p2                                 ) * 2^e
+        //         = buffer * 10^-m + 10^-m * (1/10 * (10 * p2)                   ) * 2^e
+        //         = buffer * 10^-m + 10^-m * (1/10 * ((10*p2 div 2^-e) * 2^-e + (10*p2 mod 2^-e)) * 2^e
+        //
+        JSON_ASSERT(p2 <= (std::numeric_limits<std::uint64_t>::max)() / 10);
+        p2 *= 10;
+        const std::uint64_t d = p2 >> -one.e;     // d = (10 * p2) div 2^-e
+        const std::uint64_t r = p2 & (one.f - 1); // r = (10 * p2) mod 2^-e
+        //
+        //      M+ = buffer * 10^-m + 10^-m * (1/10 * (d * 2^-e + r) * 2^e
+        //         = buffer * 10^-m + 10^-m * (1/10 * (d + r * 2^e))
+        //         = (buffer * 10 + d) * 10^(-m-1) + 10^(-m-1) * r * 2^e
+        //
+        JSON_ASSERT(d <= 9);
+        buffer[length++] = static_cast<char>('0' + d); // buffer := buffer * 10 + d
+        //
+        //      M+ = buffer * 10^(-m-1) + 10^(-m-1) * r * 2^e
+        //
+        p2 = r;
+        m++;
+        //
+        //      M+ = buffer * 10^-m + 10^-m * p2 * 2^e
+        // Invariant restored.
 
-            case value_t::string:
-            {
-                o->write_character('\"');
-                dump_escaped(*val.m_value.string, ensure_ascii);
-                o->write_character('\"');
-                return;
-            }
+        // Check if enough digits have been generated.
+        //
+        //      10^-m * p2 * 2^e <= delta * 2^e
+        //              p2 * 2^e <= 10^m * delta * 2^e
+        //                    p2 <= 10^m * delta
+        delta *= 10;
+        dist  *= 10;
+        if (p2 <= delta)
+        {
+            break;
+        }
+    }
 
-            case value_t::boolean:
-            {
-                if (val.m_value.boolean)
-                {
-                    o->write_characters("true", 4);
-                }
-                else
-                {
-                    o->write_characters("false", 5);
-                }
-                return;
-            }
+    // V = buffer * 10^-m, with M- <= V <= M+.
 
-            case value_t::number_integer:
-            {
-                dump_integer(val.m_value.number_integer);
-                return;
-            }
+    decimal_exponent -= m;
 
-            case value_t::number_unsigned:
-            {
-                dump_integer(val.m_value.number_unsigned);
-                return;
-            }
+    // 1 ulp in the decimal representation is now 10^-m.
+    // Since delta and dist are now scaled by 10^m, we need to do the
+    // same with ulp in order to keep the units in sync.
+    //
+    //      10^m * 10^-m = 1 = 2^-e * 2^e = ten_m * 2^e
+    //
+    const std::uint64_t ten_m = one.f;
+    grisu2_round(buffer, length, dist, delta, p2, ten_m);
 
-            case value_t::number_float:
-            {
-                dump_float(val.m_value.number_float);
-                return;
-            }
+    // By construction this algorithm generates the shortest possible decimal
+    // number (Loitsch, Theorem 6.2) which rounds back to w.
+    // For an input number of precision p, at least
+    //
+    //      N = 1 + ceil(p * log_10(2))
+    //
+    // decimal digits are sufficient to identify all binary floating-point
+    // numbers (Matula, "In-and-Out conversions").
+    // This implies that the algorithm does not produce more than N decimal
+    // digits.
+    //
+    //      N = 17 for p = 53 (IEEE double precision)
+    //      N = 9  for p = 24 (IEEE single precision)
+}
 
-            case value_t::discarded:
-            {
-                o->write_characters("<discarded>", 11);
-                return;
-            }
+/*!
+v = buf * 10^decimal_exponent
+len is the length of the buffer (number of decimal digits)
+The buffer must be large enough, i.e. >= max_digits10.
+*/
+JSON_HEDLEY_NON_NULL(1)
+inline void grisu2(char* buf, int& len, int& decimal_exponent,
+                   diyfp m_minus, diyfp v, diyfp m_plus)
+{
+    JSON_ASSERT(m_plus.e == m_minus.e);
+    JSON_ASSERT(m_plus.e == v.e);
 
-            case value_t::null:
-            {
-                o->write_characters("null", 4);
-                return;
-            }
-        }
-    }
+    //  --------(-----------------------+-----------------------)--------    (A)
+    //          m-                      v                       m+
+    //
+    //  --------------------(-----------+-----------------------)--------    (B)
+    //                      m-          v                       m+
+    //
+    // First scale v (and m- and m+) such that the exponent is in the range
+    // [alpha, gamma].
 
-  private:
-    /*!
-    @brief dump escaped string
+    const cached_power cached = get_cached_power_for_binary_exponent(m_plus.e);
 
-    Escape a string by replacing certain special characters by a sequence of an
-    escape character (backslash) and another character and other control
-    characters by a sequence of "\u" followed by a four-digit hex
-    representation. The escaped string is written to output stream @a o.
+    const diyfp c_minus_k(cached.f, cached.e); // = c ~= 10^-k
 
-    @param[in] s  the string to escape
-    @param[in] ensure_ascii  whether to escape non-ASCII characters with
-                             \uXXXX sequences
+    // The exponent of the products is = v.e + c_minus_k.e + q and is in the range [alpha,gamma]
+    const diyfp w       = diyfp::mul(v,       c_minus_k);
+    const diyfp w_minus = diyfp::mul(m_minus, c_minus_k);
+    const diyfp w_plus  = diyfp::mul(m_plus,  c_minus_k);
 
-    @complexity Linear in the length of string @a s.
-    */
-    void dump_escaped(const string_t& s, const bool ensure_ascii)
-    {
-        uint32_t codepoint;
-        uint8_t state = UTF8_ACCEPT;
-        std::size_t bytes = 0;  // number of bytes written to string_buffer
+    //  ----(---+---)---------------(---+---)---------------(---+---)----
+    //          w-                      w                       w+
+    //          = c*m-                  = c*v                   = c*m+
+    //
+    // diyfp::mul rounds its result and c_minus_k is approximated too. w, w- and
+    // w+ are now off by a small amount.
+    // In fact:
+    //
+    //      w - v * 10^k < 1 ulp
+    //
+    // To account for this inaccuracy, add resp. subtract 1 ulp.
+    //
+    //  --------+---[---------------(---+---)---------------]---+--------
+    //          w-  M-                  w                   M+  w+
+    //
+    // Now any number in [M-, M+] (bounds included) will round to w when input,
+    // regardless of how the input rounding algorithm breaks ties.
+    //
+    // And digit_gen generates the shortest possible such number in [M-, M+].
+    // Note that this does not mean that Grisu2 always generates the shortest
+    // possible number in the interval (m-, m+).
+    const diyfp M_minus(w_minus.f + 1, w_minus.e);
+    const diyfp M_plus (w_plus.f  - 1, w_plus.e );
 
-        // number of bytes written at the point of the last valid byte
-        std::size_t bytes_after_last_accept = 0;
-        std::size_t undumped_chars = 0;
+    decimal_exponent = -cached.k; // = -(-k) = k
 
-        for (std::size_t i = 0; i < s.size(); ++i)
-        {
-            const auto byte = static_cast<uint8_t>(s[i]);
+    grisu2_digit_gen(buf, len, decimal_exponent, M_minus, w, M_plus);
+}
 
-            switch (decode(state, codepoint, byte))
-            {
-                case UTF8_ACCEPT:  // decode found a new code point
-                {
-                    switch (codepoint)
-                    {
-                        case 0x08: // backspace
-                        {
-                            string_buffer[bytes++] = '\\';
-                            string_buffer[bytes++] = 'b';
-                            break;
-                        }
+/*!
+v = buf * 10^decimal_exponent
+len is the length of the buffer (number of decimal digits)
+The buffer must be large enough, i.e. >= max_digits10.
+*/
+template<typename FloatType>
+JSON_HEDLEY_NON_NULL(1)
+void grisu2(char* buf, int& len, int& decimal_exponent, FloatType value)
+{
+    static_assert(diyfp::kPrecision >= std::numeric_limits<FloatType>::digits + 3,
+                  "internal error: not enough precision");
 
-                        case 0x09: // horizontal tab
-                        {
-                            string_buffer[bytes++] = '\\';
-                            string_buffer[bytes++] = 't';
-                            break;
-                        }
+    JSON_ASSERT(std::isfinite(value));
+    JSON_ASSERT(value > 0);
+
+    // If the neighbors (and boundaries) of 'value' are always computed for double-precision
+    // numbers, all float's can be recovered using strtod (and strtof). However, the resulting
+    // decimal representations are not exactly "short".
+    //
+    // The documentation for 'std::to_chars' (https://en.cppreference.com/w/cpp/utility/to_chars)
+    // says "value is converted to a string as if by std::sprintf in the default ("C") locale"
+    // and since sprintf promotes float's to double's, I think this is exactly what 'std::to_chars'
+    // does.
+    // On the other hand, the documentation for 'std::to_chars' requires that "parsing the
+    // representation using the corresponding std::from_chars function recovers value exactly". That
+    // indicates that single precision floating-point numbers should be recovered using
+    // 'std::strtof'.
+    //
+    // NB: If the neighbors are computed for single-precision numbers, there is a single float
+    //     (7.0385307e-26f) which can't be recovered using strtod. The resulting double precision
+    //     value is off by 1 ulp.
+#if 0
+    const boundaries w = compute_boundaries(static_cast<double>(value));
+#else
+    const boundaries w = compute_boundaries(value);
+#endif
 
-                        case 0x0A: // newline
-                        {
-                            string_buffer[bytes++] = '\\';
-                            string_buffer[bytes++] = 'n';
-                            break;
-                        }
+    grisu2(buf, len, decimal_exponent, w.minus, w.w, w.plus);
+}
 
-                        case 0x0C: // formfeed
-                        {
-                            string_buffer[bytes++] = '\\';
-                            string_buffer[bytes++] = 'f';
-                            break;
-                        }
+/*!
+@brief appends a decimal representation of e to buf
+@return a pointer to the element following the exponent.
+@pre -1000 < e < 1000
+*/
+JSON_HEDLEY_NON_NULL(1)
+JSON_HEDLEY_RETURNS_NON_NULL
+inline char* append_exponent(char* buf, int e)
+{
+    JSON_ASSERT(e > -1000);
+    JSON_ASSERT(e <  1000);
 
-                        case 0x0D: // carriage return
-                        {
-                            string_buffer[bytes++] = '\\';
-                            string_buffer[bytes++] = 'r';
-                            break;
-                        }
+    if (e < 0)
+    {
+        e = -e;
+        *buf++ = '-';
+    }
+    else
+    {
+        *buf++ = '+';
+    }
 
-                        case 0x22: // quotation mark
-                        {
-                            string_buffer[bytes++] = '\\';
-                            string_buffer[bytes++] = '\"';
-                            break;
-                        }
+    auto k = static_cast<std::uint32_t>(e);
+    if (k < 10)
+    {
+        // Always print at least two digits in the exponent.
+        // This is for compatibility with printf("%g").
+        *buf++ = '0';
+        *buf++ = static_cast<char>('0' + k);
+    }
+    else if (k < 100)
+    {
+        *buf++ = static_cast<char>('0' + k / 10);
+        k %= 10;
+        *buf++ = static_cast<char>('0' + k);
+    }
+    else
+    {
+        *buf++ = static_cast<char>('0' + k / 100);
+        k %= 100;
+        *buf++ = static_cast<char>('0' + k / 10);
+        k %= 10;
+        *buf++ = static_cast<char>('0' + k);
+    }
 
-                        case 0x5C: // reverse solidus
-                        {
-                            string_buffer[bytes++] = '\\';
-                            string_buffer[bytes++] = '\\';
-                            break;
-                        }
+    return buf;
+}
 
-                        default:
-                        {
-                            // escape control characters (0x00..0x1F) or, if
-                            // ensure_ascii parameter is used, non-ASCII characters
-                            if ((codepoint <= 0x1F) or (ensure_ascii and (codepoint >= 0x7F)))
-                            {
-                                if (codepoint <= 0xFFFF)
-                                {
-                                    (std::snprintf)(string_buffer.data() + bytes, 7, "\\u%04x",
-                                                    static_cast<uint16_t>(codepoint));
-                                    bytes += 6;
-                                }
-                                else
-                                {
-                                    (std::snprintf)(string_buffer.data() + bytes, 13, "\\u%04x\\u%04x",
-                                                    static_cast<uint16_t>(0xD7C0 + (codepoint >> 10)),
-                                                    static_cast<uint16_t>(0xDC00 + (codepoint & 0x3FF)));
-                                    bytes += 12;
-                                }
-                            }
-                            else
-                            {
-                                // copy byte to buffer (all previous bytes
-                                // been copied have in default case above)
-                                string_buffer[bytes++] = s[i];
-                            }
-                            break;
-                        }
-                    }
+/*!
+@brief prettify v = buf * 10^decimal_exponent
 
-                    // write buffer and reset index; there must be 13 bytes
-                    // left, as this is the maximal number of bytes to be
-                    // written ("\uxxxx\uxxxx\0") for one code point
-                    if (string_buffer.size() - bytes < 13)
-                    {
-                        o->write_characters(string_buffer.data(), bytes);
-                        bytes = 0;
-                    }
+If v is in the range [10^min_exp, 10^max_exp) it will be printed in fixed-point
+notation. Otherwise it will be printed in exponential notation.
 
-                    // remember the byte position of this accept
-                    bytes_after_last_accept = bytes;
-                    undumped_chars = 0;
-                    break;
-                }
+@pre min_exp < 0
+@pre max_exp > 0
+*/
+JSON_HEDLEY_NON_NULL(1)
+JSON_HEDLEY_RETURNS_NON_NULL
+inline char* format_buffer(char* buf, int len, int decimal_exponent,
+                           int min_exp, int max_exp)
+{
+    JSON_ASSERT(min_exp < 0);
+    JSON_ASSERT(max_exp > 0);
 
-                case UTF8_REJECT:  // decode found invalid UTF-8 byte
-                {
-                    switch (error_handler)
-                    {
-                        case error_handler_t::strict:
-                        {
-                            std::string sn(3, '\0');
-                            (std::snprintf)(&sn[0], sn.size(), "%.2X", byte);
-                            JSON_THROW(type_error::create(316, "invalid UTF-8 byte at index " + std::to_string(i) + ": 0x" + sn));
-                        }
+    const int k = len;
+    const int n = len + decimal_exponent;
 
-                        case error_handler_t::ignore:
-                        case error_handler_t::replace:
-                        {
-                            // in case we saw this character the first time, we
-                            // would like to read it again, because the byte
-                            // may be OK for itself, but just not OK for the
-                            // previous sequence
-                            if (undumped_chars > 0)
-                            {
-                                --i;
-                            }
+    // v = buf * 10^(n-k)
+    // k is the length of the buffer (number of decimal digits)
+    // n is the position of the decimal point relative to the start of the buffer.
 
-                            // reset length buffer to the last accepted index;
-                            // thus removing/ignoring the invalid characters
-                            bytes = bytes_after_last_accept;
+    if (k <= n && n <= max_exp)
+    {
+        // digits[000]
+        // len <= max_exp + 2
 
-                            if (error_handler == error_handler_t::replace)
-                            {
-                                // add a replacement character
-                                if (ensure_ascii)
-                                {
-                                    string_buffer[bytes++] = '\\';
-                                    string_buffer[bytes++] = 'u';
-                                    string_buffer[bytes++] = 'f';
-                                    string_buffer[bytes++] = 'f';
-                                    string_buffer[bytes++] = 'f';
-                                    string_buffer[bytes++] = 'd';
-                                }
-                                else
-                                {
-                                    string_buffer[bytes++] = detail::binary_writer<BasicJsonType, char>::to_char_type('\xEF');
-                                    string_buffer[bytes++] = detail::binary_writer<BasicJsonType, char>::to_char_type('\xBF');
-                                    string_buffer[bytes++] = detail::binary_writer<BasicJsonType, char>::to_char_type('\xBD');
-                                }
-                                bytes_after_last_accept = bytes;
-                            }
+        std::memset(buf + k, '0', static_cast<size_t>(n) - static_cast<size_t>(k));
+        // Make it look like a floating-point number (#362, #378)
+        buf[n + 0] = '.';
+        buf[n + 1] = '0';
+        return buf + (static_cast<size_t>(n) + 2);
+    }
 
-                            undumped_chars = 0;
+    if (0 < n && n <= max_exp)
+    {
+        // dig.its
+        // len <= max_digits10 + 1
 
-                            // continue processing the string
-                            state = UTF8_ACCEPT;
-                            break;
-                        }
-                    }
-                    break;
-                }
+        JSON_ASSERT(k > n);
 
-                default:  // decode found yet incomplete multi-byte code point
-                {
-                    if (not ensure_ascii)
-                    {
-                        // code point will not be escaped - copy byte to buffer
-                        string_buffer[bytes++] = s[i];
-                    }
-                    ++undumped_chars;
-                    break;
-                }
-            }
-        }
+        std::memmove(buf + (static_cast<size_t>(n) + 1), buf + n, static_cast<size_t>(k) - static_cast<size_t>(n));
+        buf[n] = '.';
+        return buf + (static_cast<size_t>(k) + 1U);
+    }
 
-        // we finished processing the string
-        if (JSON_LIKELY(state == UTF8_ACCEPT))
-        {
-            // write buffer
-            if (bytes > 0)
-            {
-                o->write_characters(string_buffer.data(), bytes);
-            }
-        }
-        else
-        {
-            // we finish reading, but do not accept: string was incomplete
-            switch (error_handler)
-            {
-                case error_handler_t::strict:
-                {
-                    std::string sn(3, '\0');
-                    (std::snprintf)(&sn[0], sn.size(), "%.2X", static_cast<uint8_t>(s.back()));
-                    JSON_THROW(type_error::create(316, "incomplete UTF-8 string; last byte: 0x" + sn));
-                }
+    if (min_exp < n && n <= 0)
+    {
+        // 0.[000]digits
+        // len <= 2 + (-min_exp - 1) + max_digits10
 
-                case error_handler_t::ignore:
-                {
-                    // write all accepted bytes
-                    o->write_characters(string_buffer.data(), bytes_after_last_accept);
-                    break;
-                }
+        std::memmove(buf + (2 + static_cast<size_t>(-n)), buf, static_cast<size_t>(k));
+        buf[0] = '0';
+        buf[1] = '.';
+        std::memset(buf + 2, '0', static_cast<size_t>(-n));
+        return buf + (2U + static_cast<size_t>(-n) + static_cast<size_t>(k));
+    }
 
-                case error_handler_t::replace:
-                {
-                    // write all accepted bytes
-                    o->write_characters(string_buffer.data(), bytes_after_last_accept);
-                    // add a replacement character
-                    if (ensure_ascii)
-                    {
-                        o->write_characters("\\ufffd", 6);
-                    }
-                    else
-                    {
-                        o->write_characters("\xEF\xBF\xBD", 3);
-                    }
-                    break;
-                }
-            }
-        }
+    if (k == 1)
+    {
+        // dE+123
+        // len <= 1 + 5
+
+        buf += 1;
     }
+    else
+    {
+        // d.igitsE+123
+        // len <= max_digits10 + 1 + 5
 
-    /*!
-    @brief dump an integer
+        std::memmove(buf + 2, buf + 1, static_cast<size_t>(k) - 1);
+        buf[1] = '.';
+        buf += 1 + static_cast<size_t>(k);
+    }
 
-    Dump a given integer to output stream @a o. Works internally with
-    @a number_buffer.
+    *buf++ = 'e';
+    return append_exponent(buf, n - 1);
+}
 
-    @param[in] x  integer number (signed or unsigned) to dump
-    @tparam NumberType either @a number_integer_t or @a number_unsigned_t
-    */
-    template<typename NumberType, detail::enable_if_t<
-                 std::is_same<NumberType, number_unsigned_t>::value or
-                 std::is_same<NumberType, number_integer_t>::value,
-                 int> = 0>
-    void dump_integer(NumberType x)
-    {
-        // special case for "0"
-        if (x == 0)
-        {
-            o->write_character('0');
-            return;
-        }
+} // namespace dtoa_impl
 
-        const bool is_negative = std::is_same<NumberType, number_integer_t>::value and not (x >= 0);  // see issue #755
-        std::size_t i = 0;
+/*!
+@brief generates a decimal representation of the floating-point number value in [first, last).
 
-        while (x != 0)
-        {
-            // spare 1 byte for '\0'
-            assert(i < number_buffer.size() - 1);
+The format of the resulting decimal representation is similar to printf's %g
+format. Returns an iterator pointing past-the-end of the decimal representation.
 
-            const auto digit = std::labs(static_cast<long>(x % 10));
-            number_buffer[i++] = static_cast<char>('0' + digit);
-            x /= 10;
-        }
+@note The input number must be finite, i.e. NaN's and Inf's are not supported.
+@note The buffer must be large enough.
+@note The result is NOT null-terminated.
+*/
+template<typename FloatType>
+JSON_HEDLEY_NON_NULL(1, 2)
+JSON_HEDLEY_RETURNS_NON_NULL
+char* to_chars(char* first, const char* last, FloatType value)
+{
+    static_cast<void>(last); // maybe unused - fix warning
+    JSON_ASSERT(std::isfinite(value));
 
-        if (is_negative)
-        {
-            // make sure there is capacity for the '-'
-            assert(i < number_buffer.size() - 2);
-            number_buffer[i++] = '-';
-        }
+    // Use signbit(value) instead of (value < 0) since signbit works for -0.
+    if (std::signbit(value))
+    {
+        value = -value;
+        *first++ = '-';
+    }
 
-        std::reverse(number_buffer.begin(), number_buffer.begin() + i);
-        o->write_characters(number_buffer.data(), i);
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+    if (value == 0) // +-0
+    {
+        *first++ = '0';
+        // Make it look like a floating-point number (#362, #378)
+        *first++ = '.';
+        *first++ = '0';
+        return first;
     }
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
 
-    /*!
-    @brief dump a floating-point number
+    JSON_ASSERT(last - first >= std::numeric_limits<FloatType>::max_digits10);
 
-    Dump a given floating-point number to output stream @a o. Works internally
-    with @a number_buffer.
+    // Compute v = buffer * 10^decimal_exponent.
+    // The decimal digits are stored in the buffer, which needs to be interpreted
+    // as an unsigned decimal integer.
+    // len is the length of the buffer, i.e. the number of decimal digits.
+    int len = 0;
+    int decimal_exponent = 0;
+    dtoa_impl::grisu2(first, len, decimal_exponent, value);
 
-    @param[in] x  floating-point number to dump
-    */
-    void dump_float(number_float_t x)
-    {
-        // NaN / inf
-        if (not std::isfinite(x))
-        {
-            o->write_characters("null", 4);
-            return;
-        }
+    JSON_ASSERT(len <= std::numeric_limits<FloatType>::max_digits10);
 
-        // If number_float_t is an IEEE-754 single or double precision number,
-        // use the Grisu2 algorithm to produce short numbers which are
-        // guaranteed to round-trip, using strtof and strtod, resp.
-        //
-        // NB: The test below works if <long double> == <double>.
-        static constexpr bool is_ieee_single_or_double
-            = (std::numeric_limits<number_float_t>::is_iec559 and std::numeric_limits<number_float_t>::digits == 24 and std::numeric_limits<number_float_t>::max_exponent == 128) or
-              (std::numeric_limits<number_float_t>::is_iec559 and std::numeric_limits<number_float_t>::digits == 53 and std::numeric_limits<number_float_t>::max_exponent == 1024);
+    // Format the buffer like printf("%.*g", prec, value)
+    constexpr int kMinExp = -4;
+    // Use digits10 here to increase compatibility with version 2.
+    constexpr int kMaxExp = std::numeric_limits<FloatType>::digits10;
 
-        dump_float(x, std::integral_constant<bool, is_ieee_single_or_double>());
-    }
+    JSON_ASSERT(last - first >= kMaxExp + 2);
+    JSON_ASSERT(last - first >= 2 + (-kMinExp - 1) + std::numeric_limits<FloatType>::max_digits10);
+    JSON_ASSERT(last - first >= std::numeric_limits<FloatType>::max_digits10 + 6);
 
-    void dump_float(number_float_t x, std::true_type /*is_ieee_single_or_double*/)
-    {
-        char* begin = number_buffer.data();
-        char* end = ::nlohmann::detail::to_chars(begin, begin + number_buffer.size(), x);
+    return dtoa_impl::format_buffer(first, len, decimal_exponent, kMinExp, kMaxExp);
+}
 
-        o->write_characters(begin, static_cast<size_t>(end - begin));
-    }
+} // namespace detail
+} // namespace nlohmann
 
-    void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/)
-    {
-        // get number of digits for a float -> text -> float round-trip
-        static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10;
+// #include <nlohmann/detail/exceptions.hpp>
 
-        // the actual conversion
-        std::ptrdiff_t len = (std::snprintf)(number_buffer.data(), number_buffer.size(), "%.*g", d, x);
+// #include <nlohmann/detail/macro_scope.hpp>
 
-        // negative value indicates an error
-        assert(len > 0);
-        // check if buffer was large enough
-        assert(static_cast<std::size_t>(len) < number_buffer.size());
+// #include <nlohmann/detail/meta/cpp_future.hpp>
 
-        // erase thousands separator
-        if (thousands_sep != '\0')
-        {
-            const auto end = std::remove(number_buffer.begin(),
-                                         number_buffer.begin() + len, thousands_sep);
-            std::fill(end, number_buffer.end(), '\0');
-            assert((end - number_buffer.begin()) <= len);
-            len = (end - number_buffer.begin());
-        }
+// #include <nlohmann/detail/output/binary_writer.hpp>
 
-        // convert decimal point to '.'
-        if (decimal_point != '\0' and decimal_point != '.')
-        {
-            const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
-            if (dec_pos != number_buffer.end())
-            {
-                *dec_pos = '.';
-            }
-        }
+// #include <nlohmann/detail/output/output_adapters.hpp>
 
-        o->write_characters(number_buffer.data(), static_cast<std::size_t>(len));
+// #include <nlohmann/detail/value_t.hpp>
 
-        // determine if need to append ".0"
-        const bool value_is_int_like =
-            std::none_of(number_buffer.begin(), number_buffer.begin() + len + 1,
-                         [](char c)
-        {
-            return (c == '.' or c == 'e');
-        });
 
-        if (value_is_int_like)
-        {
-            o->write_characters(".0", 2);
-        }
-    }
+namespace nlohmann
+{
+namespace detail
+{
+///////////////////
+// serialization //
+///////////////////
+
+/// how to treat decoding errors
+enum class error_handler_t
+{
+    strict,  ///< throw a type_error exception in case of invalid UTF-8
+    replace, ///< replace invalid UTF-8 sequences with U+FFFD
+    ignore   ///< ignore invalid UTF-8 sequences
+};
+
+template<typename BasicJsonType>
+class serializer
+{
+    using string_t = typename BasicJsonType::string_t;
+    using number_float_t = typename BasicJsonType::number_float_t;
+    using number_integer_t = typename BasicJsonType::number_integer_t;
+    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    using binary_char_t = typename BasicJsonType::binary_t::value_type;
+    static constexpr std::uint8_t UTF8_ACCEPT = 0;
+    static constexpr std::uint8_t UTF8_REJECT = 1;
 
+  public:
     /*!
-    @brief check whether a string is UTF-8 encoded
+    @param[in] s  output stream to serialize to
+    @param[in] ichar  indentation character to use
+    @param[in] error_handler_  how to react on decoding errors
+    */
+    serializer(output_adapter_t<char> s, const char ichar,
+               error_handler_t error_handler_ = error_handler_t::strict)
+        : o(std::move(s))
+        , loc(std::localeconv())
+        , thousands_sep(loc->thousands_sep == nullptr ? '\0' : std::char_traits<char>::to_char_type(* (loc->thousands_sep)))
+        , decimal_point(loc->decimal_point == nullptr ? '\0' : std::char_traits<char>::to_char_type(* (loc->decimal_point)))
+        , indent_char(ichar)
+        , indent_string(512, indent_char)
+        , error_handler(error_handler_)
+    {}
 
-    The function checks each byte of a string whether it is UTF-8 encoded. The
-    result of the check is stored in the @a state parameter. The function must
-    be called initially with state 0 (accept). State 1 means the string must
-    be rejected, because the current byte is not allowed. If the string is
-    completely processed, but the state is non-zero, the string ended
-    prematurely; that is, the last byte indicated more bytes should have
-    followed.
+    // delete because of pointer members
+    serializer(const serializer&) = delete;
+    serializer& operator=(const serializer&) = delete;
+    serializer(serializer&&) = delete;
+    serializer& operator=(serializer&&) = delete;
+    ~serializer() = default;
 
-    @param[in,out] state  the state of the decoding
-    @param[in,out] codep  codepoint (valid only if resulting state is UTF8_ACCEPT)
-    @param[in] byte       next byte to decode
-    @return               new state
+    /*!
+    @brief internal implementation of the serialization function
 
-    @note The function has been edited: a std::array is used.
+    This function is called by the public member function dump and organizes
+    the serialization internally. The indentation level is propagated as
+    additional parameter. In case of arrays and objects, the function is
+    called recursively.
 
-    @copyright Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
-    @sa http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
+    - strings and object keys are escaped using `escape_string()`
+    - integer numbers are converted implicitly via `operator<<`
+    - floating-point numbers are converted to a string using `"%g"` format
+    - binary values are serialized as objects containing the subtype and the
+      byte array
+
+    @param[in] val               value to serialize
+    @param[in] pretty_print      whether the output shall be pretty-printed
+    @param[in] ensure_ascii If @a ensure_ascii is true, all non-ASCII characters
+    in the output are escaped with `\uXXXX` sequences, and the result consists
+    of ASCII characters only.
+    @param[in] indent_step       the indent level
+    @param[in] current_indent    the current indent level (only used internally)
     */
-    static uint8_t decode(uint8_t& state, uint32_t& codep, const uint8_t byte) noexcept
+    void dump(const BasicJsonType& val,
+              const bool pretty_print,
+              const bool ensure_ascii,
+              const unsigned int indent_step,
+              const unsigned int current_indent = 0)
     {
-        static const std::array<uint8_t, 400> utf8d =
+        switch (val.m_type)
         {
+            case value_t::object:
             {
-                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 00..1F
-                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20..3F
-                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 40..5F
-                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 60..7F
-                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 80..9F
-                7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // A0..BF
-                8, 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // C0..DF
-                0xA, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x4, 0x3, 0x3, // E0..EF
-                0xB, 0x6, 0x6, 0x6, 0x5, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, // F0..FF
-                0x0, 0x1, 0x2, 0x3, 0x5, 0x8, 0x7, 0x1, 0x1, 0x1, 0x4, 0x6, 0x1, 0x1, 0x1, 0x1, // s0..s0
-                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, // s1..s2
-                1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, // s3..s4
-                1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, // s5..s6
-                1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 // s7..s8
-            }
-        };
+                if (val.m_value.object->empty())
+                {
+                    o->write_characters("{}", 2);
+                    return;
+                }
+
+                if (pretty_print)
+                {
+                    o->write_characters("{\n", 2);
 
-        const uint8_t type = utf8d[byte];
+                    // variable to hold indentation for recursive calls
+                    const auto new_indent = current_indent + indent_step;
+                    if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
+                    {
+                        indent_string.resize(indent_string.size() * 2, ' ');
+                    }
 
-        codep = (state != UTF8_ACCEPT)
-                ? (byte & 0x3fu) | (codep << 6)
-                : static_cast<uint32_t>(0xff >> type) & (byte);
+                    // first n-1 elements
+                    auto i = val.m_value.object->cbegin();
+                    for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
+                    {
+                        o->write_characters(indent_string.c_str(), new_indent);
+                        o->write_character('\"');
+                        dump_escaped(i->first, ensure_ascii);
+                        o->write_characters("\": ", 3);
+                        dump(i->second, true, ensure_ascii, indent_step, new_indent);
+                        o->write_characters(",\n", 2);
+                    }
 
-        state = utf8d[256u + state * 16u + type];
-        return state;
-    }
+                    // last element
+                    JSON_ASSERT(i != val.m_value.object->cend());
+                    JSON_ASSERT(std::next(i) == val.m_value.object->cend());
+                    o->write_characters(indent_string.c_str(), new_indent);
+                    o->write_character('\"');
+                    dump_escaped(i->first, ensure_ascii);
+                    o->write_characters("\": ", 3);
+                    dump(i->second, true, ensure_ascii, indent_step, new_indent);
 
-  private:
-    /// the output of the serializer
-    output_adapter_t<char> o = nullptr;
+                    o->write_character('\n');
+                    o->write_characters(indent_string.c_str(), current_indent);
+                    o->write_character('}');
+                }
+                else
+                {
+                    o->write_character('{');
 
-    /// a (hopefully) large enough character buffer
-    std::array<char, 64> number_buffer{{}};
+                    // first n-1 elements
+                    auto i = val.m_value.object->cbegin();
+                    for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
+                    {
+                        o->write_character('\"');
+                        dump_escaped(i->first, ensure_ascii);
+                        o->write_characters("\":", 2);
+                        dump(i->second, false, ensure_ascii, indent_step, current_indent);
+                        o->write_character(',');
+                    }
 
-    /// the locale
-    const std::lconv* loc = nullptr;
-    /// the locale's thousand separator character
-    const char thousands_sep = '\0';
-    /// the locale's decimal point character
-    const char decimal_point = '\0';
+                    // last element
+                    JSON_ASSERT(i != val.m_value.object->cend());
+                    JSON_ASSERT(std::next(i) == val.m_value.object->cend());
+                    o->write_character('\"');
+                    dump_escaped(i->first, ensure_ascii);
+                    o->write_characters("\":", 2);
+                    dump(i->second, false, ensure_ascii, indent_step, current_indent);
 
-    /// string buffer
-    std::array<char, 512> string_buffer{{}};
+                    o->write_character('}');
+                }
 
-    /// the indentation character
-    const char indent_char;
-    /// the indentation string
-    string_t indent_string;
+                return;
+            }
 
-    /// error_handler how to react on decoding errors
-    const error_handler_t error_handler;
-};
-}  // namespace detail
-}  // namespace nlohmann
+            case value_t::array:
+            {
+                if (val.m_value.array->empty())
+                {
+                    o->write_characters("[]", 2);
+                    return;
+                }
 
-// #include <nlohmann/detail/json_ref.hpp>
+                if (pretty_print)
+                {
+                    o->write_characters("[\n", 2);
 
+                    // variable to hold indentation for recursive calls
+                    const auto new_indent = current_indent + indent_step;
+                    if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
+                    {
+                        indent_string.resize(indent_string.size() * 2, ' ');
+                    }
 
-#include <initializer_list>
-#include <utility>
+                    // first n-1 elements
+                    for (auto i = val.m_value.array->cbegin();
+                            i != val.m_value.array->cend() - 1; ++i)
+                    {
+                        o->write_characters(indent_string.c_str(), new_indent);
+                        dump(*i, true, ensure_ascii, indent_step, new_indent);
+                        o->write_characters(",\n", 2);
+                    }
 
-// #include <nlohmann/detail/meta/type_traits.hpp>
+                    // last element
+                    JSON_ASSERT(!val.m_value.array->empty());
+                    o->write_characters(indent_string.c_str(), new_indent);
+                    dump(val.m_value.array->back(), true, ensure_ascii, indent_step, new_indent);
 
+                    o->write_character('\n');
+                    o->write_characters(indent_string.c_str(), current_indent);
+                    o->write_character(']');
+                }
+                else
+                {
+                    o->write_character('[');
 
-namespace nlohmann
-{
-namespace detail
-{
-template<typename BasicJsonType>
-class json_ref
-{
-  public:
-    using value_type = BasicJsonType;
+                    // first n-1 elements
+                    for (auto i = val.m_value.array->cbegin();
+                            i != val.m_value.array->cend() - 1; ++i)
+                    {
+                        dump(*i, false, ensure_ascii, indent_step, current_indent);
+                        o->write_character(',');
+                    }
 
-    json_ref(value_type&& value)
-        : owned_value(std::move(value)), value_ref(&owned_value), is_rvalue(true)
-    {}
+                    // last element
+                    JSON_ASSERT(!val.m_value.array->empty());
+                    dump(val.m_value.array->back(), false, ensure_ascii, indent_step, current_indent);
 
-    json_ref(const value_type& value)
-        : value_ref(const_cast<value_type*>(&value)), is_rvalue(false)
-    {}
+                    o->write_character(']');
+                }
 
-    json_ref(std::initializer_list<json_ref> init)
-        : owned_value(init), value_ref(&owned_value), is_rvalue(true)
-    {}
+                return;
+            }
 
-    template <
-        class... Args,
-        enable_if_t<std::is_constructible<value_type, Args...>::value, int> = 0 >
-    json_ref(Args && ... args)
-        : owned_value(std::forward<Args>(args)...), value_ref(&owned_value),
-          is_rvalue(true) {}
+            case value_t::string:
+            {
+                o->write_character('\"');
+                dump_escaped(*val.m_value.string, ensure_ascii);
+                o->write_character('\"');
+                return;
+            }
 
-    // class should be movable only
-    json_ref(json_ref&&) = default;
-    json_ref(const json_ref&) = delete;
-    json_ref& operator=(const json_ref&) = delete;
-    json_ref& operator=(json_ref&&) = delete;
-    ~json_ref() = default;
+            case value_t::binary:
+            {
+                if (pretty_print)
+                {
+                    o->write_characters("{\n", 2);
 
-    value_type moved_or_copied() const
-    {
-        if (is_rvalue)
-        {
-            return std::move(*value_ref);
-        }
-        return *value_ref;
-    }
+                    // variable to hold indentation for recursive calls
+                    const auto new_indent = current_indent + indent_step;
+                    if (JSON_HEDLEY_UNLIKELY(indent_string.size() < new_indent))
+                    {
+                        indent_string.resize(indent_string.size() * 2, ' ');
+                    }
 
-    value_type const& operator*() const
-    {
-        return *static_cast<value_type const*>(value_ref);
-    }
+                    o->write_characters(indent_string.c_str(), new_indent);
 
-    value_type const* operator->() const
-    {
-        return static_cast<value_type const*>(value_ref);
-    }
+                    o->write_characters("\"bytes\": [", 10);
 
-  private:
-    mutable value_type owned_value = nullptr;
-    value_type* value_ref = nullptr;
-    const bool is_rvalue;
-};
-}  // namespace detail
-}  // namespace nlohmann
+                    if (!val.m_value.binary->empty())
+                    {
+                        for (auto i = val.m_value.binary->cbegin();
+                                i != val.m_value.binary->cend() - 1; ++i)
+                        {
+                            dump_integer(*i);
+                            o->write_characters(", ", 2);
+                        }
+                        dump_integer(val.m_value.binary->back());
+                    }
 
-// #include <nlohmann/detail/json_pointer.hpp>
+                    o->write_characters("],\n", 3);
+                    o->write_characters(indent_string.c_str(), new_indent);
 
+                    o->write_characters("\"subtype\": ", 11);
+                    if (val.m_value.binary->has_subtype())
+                    {
+                        dump_integer(val.m_value.binary->subtype());
+                    }
+                    else
+                    {
+                        o->write_characters("null", 4);
+                    }
+                    o->write_character('\n');
+                    o->write_characters(indent_string.c_str(), current_indent);
+                    o->write_character('}');
+                }
+                else
+                {
+                    o->write_characters("{\"bytes\":[", 10);
 
-#include <cassert> // assert
-#include <numeric> // accumulate
-#include <string> // string
-#include <vector> // vector
+                    if (!val.m_value.binary->empty())
+                    {
+                        for (auto i = val.m_value.binary->cbegin();
+                                i != val.m_value.binary->cend() - 1; ++i)
+                        {
+                            dump_integer(*i);
+                            o->write_character(',');
+                        }
+                        dump_integer(val.m_value.binary->back());
+                    }
 
-// #include <nlohmann/detail/macro_scope.hpp>
+                    o->write_characters("],\"subtype\":", 12);
+                    if (val.m_value.binary->has_subtype())
+                    {
+                        dump_integer(val.m_value.binary->subtype());
+                        o->write_character('}');
+                    }
+                    else
+                    {
+                        o->write_characters("null}", 5);
+                    }
+                }
+                return;
+            }
 
-// #include <nlohmann/detail/exceptions.hpp>
+            case value_t::boolean:
+            {
+                if (val.m_value.boolean)
+                {
+                    o->write_characters("true", 4);
+                }
+                else
+                {
+                    o->write_characters("false", 5);
+                }
+                return;
+            }
 
-// #include <nlohmann/detail/value_t.hpp>
+            case value_t::number_integer:
+            {
+                dump_integer(val.m_value.number_integer);
+                return;
+            }
 
+            case value_t::number_unsigned:
+            {
+                dump_integer(val.m_value.number_unsigned);
+                return;
+            }
 
-namespace nlohmann
-{
-template<typename BasicJsonType>
-class json_pointer
-{
-    // allow basic_json to access private members
-    NLOHMANN_BASIC_JSON_TPL_DECLARATION
-    friend class basic_json;
+            case value_t::number_float:
+            {
+                dump_float(val.m_value.number_float);
+                return;
+            }
 
-  public:
-    /*!
-    @brief create JSON pointer
+            case value_t::discarded:
+            {
+                o->write_characters("<discarded>", 11);
+                return;
+            }
 
-    Create a JSON pointer according to the syntax described in
-    [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3).
+            case value_t::null:
+            {
+                o->write_characters("null", 4);
+                return;
+            }
 
-    @param[in] s  string representing the JSON pointer; if omitted, the empty
-                  string is assumed which references the whole JSON value
+            default:            // LCOV_EXCL_LINE
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+        }
+    }
 
-    @throw parse_error.107 if the given JSON pointer @a s is nonempty and does
-                           not begin with a slash (`/`); see example below
+  JSON_PRIVATE_UNLESS_TESTED:
+    /*!
+    @brief dump escaped string
 
-    @throw parse_error.108 if a tilde (`~`) in the given JSON pointer @a s is
-    not followed by `0` (representing `~`) or `1` (representing `/`); see
-    example below
+    Escape a string by replacing certain special characters by a sequence of an
+    escape character (backslash) and another character and other control
+    characters by a sequence of "\u" followed by a four-digit hex
+    representation. The escaped string is written to output stream @a o.
 
-    @liveexample{The example shows the construction several valid JSON pointers
-    as well as the exceptional behavior.,json_pointer}
+    @param[in] s  the string to escape
+    @param[in] ensure_ascii  whether to escape non-ASCII characters with
+                             \uXXXX sequences
 
-    @since version 2.0.0
+    @complexity Linear in the length of string @a s.
     */
-    explicit json_pointer(const std::string& s = "")
-        : reference_tokens(split(s))
-    {}
+    void dump_escaped(const string_t& s, const bool ensure_ascii)
+    {
+        std::uint32_t codepoint{};
+        std::uint8_t state = UTF8_ACCEPT;
+        std::size_t bytes = 0;  // number of bytes written to string_buffer
 
-    /*!
-    @brief return a string representation of the JSON pointer
+        // number of bytes written at the point of the last valid byte
+        std::size_t bytes_after_last_accept = 0;
+        std::size_t undumped_chars = 0;
 
-    @invariant For each JSON pointer `ptr`, it holds:
-    @code {.cpp}
-    ptr == json_pointer(ptr.to_string());
-    @endcode
+        for (std::size_t i = 0; i < s.size(); ++i)
+        {
+            const auto byte = static_cast<std::uint8_t>(s[i]);
 
-    @return a string representation of the JSON pointer
+            switch (decode(state, codepoint, byte))
+            {
+                case UTF8_ACCEPT:  // decode found a new code point
+                {
+                    switch (codepoint)
+                    {
+                        case 0x08: // backspace
+                        {
+                            string_buffer[bytes++] = '\\';
+                            string_buffer[bytes++] = 'b';
+                            break;
+                        }
 
-    @liveexample{The example shows the result of `to_string`.,
-    json_pointer__to_string}
+                        case 0x09: // horizontal tab
+                        {
+                            string_buffer[bytes++] = '\\';
+                            string_buffer[bytes++] = 't';
+                            break;
+                        }
 
-    @since version 2.0.0
-    */
-    std::string to_string() const
-    {
-        return std::accumulate(reference_tokens.begin(), reference_tokens.end(),
-                               std::string{},
-                               [](const std::string & a, const std::string & b)
-        {
-            return a + "/" + escape(b);
-        });
-    }
+                        case 0x0A: // newline
+                        {
+                            string_buffer[bytes++] = '\\';
+                            string_buffer[bytes++] = 'n';
+                            break;
+                        }
 
-    /// @copydoc to_string()
-    operator std::string() const
-    {
-        return to_string();
-    }
+                        case 0x0C: // formfeed
+                        {
+                            string_buffer[bytes++] = '\\';
+                            string_buffer[bytes++] = 'f';
+                            break;
+                        }
 
-    /*!
-    @param[in] s  reference token to be converted into an array index
+                        case 0x0D: // carriage return
+                        {
+                            string_buffer[bytes++] = '\\';
+                            string_buffer[bytes++] = 'r';
+                            break;
+                        }
 
-    @return integer representation of @a s
+                        case 0x22: // quotation mark
+                        {
+                            string_buffer[bytes++] = '\\';
+                            string_buffer[bytes++] = '\"';
+                            break;
+                        }
 
-    @throw out_of_range.404 if string @a s could not be converted to an integer
-    */
-    static int array_index(const std::string& s)
-    {
-        std::size_t processed_chars = 0;
-        const int res = std::stoi(s, &processed_chars);
+                        case 0x5C: // reverse solidus
+                        {
+                            string_buffer[bytes++] = '\\';
+                            string_buffer[bytes++] = '\\';
+                            break;
+                        }
 
-        // check if the string was completely read
-        if (JSON_UNLIKELY(processed_chars != s.size()))
-        {
-            JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + s + "'"));
-        }
+                        default:
+                        {
+                            // escape control characters (0x00..0x1F) or, if
+                            // ensure_ascii parameter is used, non-ASCII characters
+                            if ((codepoint <= 0x1F) || (ensure_ascii && (codepoint >= 0x7F)))
+                            {
+                                if (codepoint <= 0xFFFF)
+                                {
+                                    // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                                    (std::snprintf)(string_buffer.data() + bytes, 7, "\\u%04x",
+                                                    static_cast<std::uint16_t>(codepoint));
+                                    bytes += 6;
+                                }
+                                else
+                                {
+                                    // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                                    (std::snprintf)(string_buffer.data() + bytes, 13, "\\u%04x\\u%04x",
+                                                    static_cast<std::uint16_t>(0xD7C0u + (codepoint >> 10u)),
+                                                    static_cast<std::uint16_t>(0xDC00u + (codepoint & 0x3FFu)));
+                                    bytes += 12;
+                                }
+                            }
+                            else
+                            {
+                                // copy byte to buffer (all previous bytes
+                                // been copied have in default case above)
+                                string_buffer[bytes++] = s[i];
+                            }
+                            break;
+                        }
+                    }
 
-        return res;
-    }
+                    // write buffer and reset index; there must be 13 bytes
+                    // left, as this is the maximal number of bytes to be
+                    // written ("\uxxxx\uxxxx\0") for one code point
+                    if (string_buffer.size() - bytes < 13)
+                    {
+                        o->write_characters(string_buffer.data(), bytes);
+                        bytes = 0;
+                    }
 
-  private:
-    /*!
-    @brief remove and return last reference pointer
-    @throw out_of_range.405 if JSON pointer has no parent
-    */
-    std::string pop_back()
-    {
-        if (JSON_UNLIKELY(is_root()))
-        {
-            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent"));
-        }
+                    // remember the byte position of this accept
+                    bytes_after_last_accept = bytes;
+                    undumped_chars = 0;
+                    break;
+                }
 
-        auto last = reference_tokens.back();
-        reference_tokens.pop_back();
-        return last;
-    }
+                case UTF8_REJECT:  // decode found invalid UTF-8 byte
+                {
+                    switch (error_handler)
+                    {
+                        case error_handler_t::strict:
+                        {
+                            std::string sn(9, '\0');
+                            // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                            (std::snprintf)(&sn[0], sn.size(), "%.2X", byte);
+                            JSON_THROW(type_error::create(316, "invalid UTF-8 byte at index " + std::to_string(i) + ": 0x" + sn, BasicJsonType()));
+                        }
 
-    /// return whether pointer points to the root document
-    bool is_root() const noexcept
-    {
-        return reference_tokens.empty();
-    }
+                        case error_handler_t::ignore:
+                        case error_handler_t::replace:
+                        {
+                            // in case we saw this character the first time, we
+                            // would like to read it again, because the byte
+                            // may be OK for itself, but just not OK for the
+                            // previous sequence
+                            if (undumped_chars > 0)
+                            {
+                                --i;
+                            }
 
-    json_pointer top() const
-    {
-        if (JSON_UNLIKELY(is_root()))
-        {
-            JSON_THROW(detail::out_of_range::create(405, "JSON pointer has no parent"));
-        }
+                            // reset length buffer to the last accepted index;
+                            // thus removing/ignoring the invalid characters
+                            bytes = bytes_after_last_accept;
 
-        json_pointer result = *this;
-        result.reference_tokens = {reference_tokens[0]};
-        return result;
-    }
+                            if (error_handler == error_handler_t::replace)
+                            {
+                                // add a replacement character
+                                if (ensure_ascii)
+                                {
+                                    string_buffer[bytes++] = '\\';
+                                    string_buffer[bytes++] = 'u';
+                                    string_buffer[bytes++] = 'f';
+                                    string_buffer[bytes++] = 'f';
+                                    string_buffer[bytes++] = 'f';
+                                    string_buffer[bytes++] = 'd';
+                                }
+                                else
+                                {
+                                    string_buffer[bytes++] = detail::binary_writer<BasicJsonType, char>::to_char_type('\xEF');
+                                    string_buffer[bytes++] = detail::binary_writer<BasicJsonType, char>::to_char_type('\xBF');
+                                    string_buffer[bytes++] = detail::binary_writer<BasicJsonType, char>::to_char_type('\xBD');
+                                }
 
-    /*!
-    @brief create and return a reference to the pointed to value
+                                // write buffer and reset index; there must be 13 bytes
+                                // left, as this is the maximal number of bytes to be
+                                // written ("\uxxxx\uxxxx\0") for one code point
+                                if (string_buffer.size() - bytes < 13)
+                                {
+                                    o->write_characters(string_buffer.data(), bytes);
+                                    bytes = 0;
+                                }
 
-    @complexity Linear in the number of reference tokens.
+                                bytes_after_last_accept = bytes;
+                            }
 
-    @throw parse_error.109 if array index is not a number
-    @throw type_error.313 if value cannot be unflattened
-    */
-    BasicJsonType& get_and_create(BasicJsonType& j) const
-    {
-        using size_type = typename BasicJsonType::size_type;
-        auto result = &j;
+                            undumped_chars = 0;
 
-        // in case no reference tokens exist, return a reference to the JSON value
-        // j which will be overwritten by a primitive value
-        for (const auto& reference_token : reference_tokens)
+                            // continue processing the string
+                            state = UTF8_ACCEPT;
+                            break;
+                        }
+
+                        default:            // LCOV_EXCL_LINE
+                            JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+                    }
+                    break;
+                }
+
+                default:  // decode found yet incomplete multi-byte code point
+                {
+                    if (!ensure_ascii)
+                    {
+                        // code point will not be escaped - copy byte to buffer
+                        string_buffer[bytes++] = s[i];
+                    }
+                    ++undumped_chars;
+                    break;
+                }
+            }
+        }
+
+        // we finished processing the string
+        if (JSON_HEDLEY_LIKELY(state == UTF8_ACCEPT))
+        {
+            // write buffer
+            if (bytes > 0)
+            {
+                o->write_characters(string_buffer.data(), bytes);
+            }
+        }
+        else
         {
-            switch (result->m_type)
+            // we finish reading, but do not accept: string was incomplete
+            switch (error_handler)
             {
-                case detail::value_t::null:
+                case error_handler_t::strict:
                 {
-                    if (reference_token == "0")
-                    {
-                        // start a new array if reference token is 0
-                        result = &result->operator[](0);
-                    }
-                    else
-                    {
-                        // start a new object otherwise
-                        result = &result->operator[](reference_token);
-                    }
-                    break;
+                    std::string sn(9, '\0');
+                    // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+                    (std::snprintf)(&sn[0], sn.size(), "%.2X", static_cast<std::uint8_t>(s.back()));
+                    JSON_THROW(type_error::create(316, "incomplete UTF-8 string; last byte: 0x" + sn, BasicJsonType()));
                 }
 
-                case detail::value_t::object:
+                case error_handler_t::ignore:
                 {
-                    // create an entry in the object
-                    result = &result->operator[](reference_token);
+                    // write all accepted bytes
+                    o->write_characters(string_buffer.data(), bytes_after_last_accept);
                     break;
                 }
 
-                case detail::value_t::array:
+                case error_handler_t::replace:
                 {
-                    // create an entry in the array
-                    JSON_TRY
+                    // write all accepted bytes
+                    o->write_characters(string_buffer.data(), bytes_after_last_accept);
+                    // add a replacement character
+                    if (ensure_ascii)
                     {
-                        result = &result->operator[](static_cast<size_type>(array_index(reference_token)));
+                        o->write_characters("\\ufffd", 6);
                     }
-                    JSON_CATCH(std::invalid_argument&)
+                    else
                     {
-                        JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
+                        o->write_characters("\xEF\xBF\xBD", 3);
                     }
                     break;
                 }
 
-                /*
-                The following code is only reached if there exists a reference
-                token _and_ the current value is primitive. In this case, we have
-                an error situation, because primitive values may only occur as
-                single value; that is, with an empty list of reference tokens.
-                */
-                default:
-                    JSON_THROW(detail::type_error::create(313, "invalid value to unflatten"));
+                default:            // LCOV_EXCL_LINE
+                    JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
             }
         }
-
-        return *result;
     }
 
+  private:
     /*!
-    @brief return a reference to the pointed to value
-
-    @note This version does not throw if a value is not present, but tries to
-          create nested values instead. For instance, calling this function
-          with pointer `"/this/that"` on a null value is equivalent to calling
-          `operator[]("this").operator[]("that")` on that value, effectively
-          changing the null value to an object.
-
-    @param[in] ptr  a JSON value
-
-    @return reference to the JSON value pointed to by the JSON pointer
+    @brief count digits
 
-    @complexity Linear in the length of the JSON pointer.
+    Count the number of decimal (base 10) digits for an input unsigned integer.
 
-    @throw parse_error.106   if an array index begins with '0'
-    @throw parse_error.109   if an array index was not a number
-    @throw out_of_range.404  if the JSON pointer can not be resolved
+    @param[in] x  unsigned integer number to count its digits
+    @return    number of decimal digits
     */
-    BasicJsonType& get_unchecked(BasicJsonType* ptr) const
+    inline unsigned int count_digits(number_unsigned_t x) noexcept
     {
-        using size_type = typename BasicJsonType::size_type;
-        for (const auto& reference_token : reference_tokens)
+        unsigned int n_digits = 1;
+        for (;;)
         {
-            // convert null values to arrays or objects before continuing
-            if (ptr->m_type == detail::value_t::null)
+            if (x < 10)
             {
-                // check if reference token is a number
-                const bool nums =
-                    std::all_of(reference_token.begin(), reference_token.end(),
-                                [](const char x)
-                {
-                    return (x >= '0' and x <= '9');
-                });
-
-                // change value to array for numbers or "-" or to object otherwise
-                *ptr = (nums or reference_token == "-")
-                       ? detail::value_t::array
-                       : detail::value_t::object;
+                return n_digits;
             }
-
-            switch (ptr->m_type)
+            if (x < 100)
             {
-                case detail::value_t::object:
-                {
-                    // use unchecked object access
-                    ptr = &ptr->operator[](reference_token);
-                    break;
-                }
-
-                case detail::value_t::array:
-                {
-                    // error condition (cf. RFC 6901, Sect. 4)
-                    if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0'))
-                    {
-                        JSON_THROW(detail::parse_error::create(106, 0,
-                                                               "array index '" + reference_token +
-                                                               "' must not begin with '0'"));
-                    }
-
-                    if (reference_token == "-")
-                    {
-                        // explicitly treat "-" as index beyond the end
-                        ptr = &ptr->operator[](ptr->m_value.array->size());
-                    }
-                    else
-                    {
-                        // convert array index to number; unchecked access
-                        JSON_TRY
-                        {
-                            ptr = &ptr->operator[](
-                                static_cast<size_type>(array_index(reference_token)));
-                        }
-                        JSON_CATCH(std::invalid_argument&)
-                        {
-                            JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                        }
-                    }
-                    break;
-                }
-
-                default:
-                    JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
+                return n_digits + 1;
+            }
+            if (x < 1000)
+            {
+                return n_digits + 2;
+            }
+            if (x < 10000)
+            {
+                return n_digits + 3;
             }
+            x = x / 10000u;
+            n_digits += 4;
         }
-
-        return *ptr;
     }
 
     /*!
-    @throw parse_error.106   if an array index begins with '0'
-    @throw parse_error.109   if an array index was not a number
-    @throw out_of_range.402  if the array index '-' is used
-    @throw out_of_range.404  if the JSON pointer can not be resolved
+    @brief dump an integer
+
+    Dump a given integer to output stream @a o. Works internally with
+    @a number_buffer.
+
+    @param[in] x  integer number (signed or unsigned) to dump
+    @tparam NumberType either @a number_integer_t or @a number_unsigned_t
     */
-    BasicJsonType& get_checked(BasicJsonType* ptr) const
+    template < typename NumberType, detail::enable_if_t <
+                   std::is_integral<NumberType>::value ||
+                   std::is_same<NumberType, number_unsigned_t>::value ||
+                   std::is_same<NumberType, number_integer_t>::value ||
+                   std::is_same<NumberType, binary_char_t>::value,
+                   int > = 0 >
+    void dump_integer(NumberType x)
     {
-        using size_type = typename BasicJsonType::size_type;
-        for (const auto& reference_token : reference_tokens)
+        static constexpr std::array<std::array<char, 2>, 100> digits_to_99
         {
-            switch (ptr->m_type)
             {
-                case detail::value_t::object:
-                {
-                    // note: at performs range check
-                    ptr = &ptr->at(reference_token);
-                    break;
-                }
+                {{'0', '0'}}, {{'0', '1'}}, {{'0', '2'}}, {{'0', '3'}}, {{'0', '4'}}, {{'0', '5'}}, {{'0', '6'}}, {{'0', '7'}}, {{'0', '8'}}, {{'0', '9'}},
+                {{'1', '0'}}, {{'1', '1'}}, {{'1', '2'}}, {{'1', '3'}}, {{'1', '4'}}, {{'1', '5'}}, {{'1', '6'}}, {{'1', '7'}}, {{'1', '8'}}, {{'1', '9'}},
+                {{'2', '0'}}, {{'2', '1'}}, {{'2', '2'}}, {{'2', '3'}}, {{'2', '4'}}, {{'2', '5'}}, {{'2', '6'}}, {{'2', '7'}}, {{'2', '8'}}, {{'2', '9'}},
+                {{'3', '0'}}, {{'3', '1'}}, {{'3', '2'}}, {{'3', '3'}}, {{'3', '4'}}, {{'3', '5'}}, {{'3', '6'}}, {{'3', '7'}}, {{'3', '8'}}, {{'3', '9'}},
+                {{'4', '0'}}, {{'4', '1'}}, {{'4', '2'}}, {{'4', '3'}}, {{'4', '4'}}, {{'4', '5'}}, {{'4', '6'}}, {{'4', '7'}}, {{'4', '8'}}, {{'4', '9'}},
+                {{'5', '0'}}, {{'5', '1'}}, {{'5', '2'}}, {{'5', '3'}}, {{'5', '4'}}, {{'5', '5'}}, {{'5', '6'}}, {{'5', '7'}}, {{'5', '8'}}, {{'5', '9'}},
+                {{'6', '0'}}, {{'6', '1'}}, {{'6', '2'}}, {{'6', '3'}}, {{'6', '4'}}, {{'6', '5'}}, {{'6', '6'}}, {{'6', '7'}}, {{'6', '8'}}, {{'6', '9'}},
+                {{'7', '0'}}, {{'7', '1'}}, {{'7', '2'}}, {{'7', '3'}}, {{'7', '4'}}, {{'7', '5'}}, {{'7', '6'}}, {{'7', '7'}}, {{'7', '8'}}, {{'7', '9'}},
+                {{'8', '0'}}, {{'8', '1'}}, {{'8', '2'}}, {{'8', '3'}}, {{'8', '4'}}, {{'8', '5'}}, {{'8', '6'}}, {{'8', '7'}}, {{'8', '8'}}, {{'8', '9'}},
+                {{'9', '0'}}, {{'9', '1'}}, {{'9', '2'}}, {{'9', '3'}}, {{'9', '4'}}, {{'9', '5'}}, {{'9', '6'}}, {{'9', '7'}}, {{'9', '8'}}, {{'9', '9'}},
+            }
+        };
 
-                case detail::value_t::array:
-                {
-                    if (JSON_UNLIKELY(reference_token == "-"))
-                    {
-                        // "-" always fails the range check
-                        JSON_THROW(detail::out_of_range::create(402,
-                                                                "array index '-' (" + std::to_string(ptr->m_value.array->size()) +
-                                                                ") is out of range"));
-                    }
+        // special case for "0"
+        if (x == 0)
+        {
+            o->write_character('0');
+            return;
+        }
 
-                    // error condition (cf. RFC 6901, Sect. 4)
-                    if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0'))
-                    {
-                        JSON_THROW(detail::parse_error::create(106, 0,
-                                                               "array index '" + reference_token +
-                                                               "' must not begin with '0'"));
-                    }
+        // use a pointer to fill the buffer
+        auto buffer_ptr = number_buffer.begin(); // NOLINT(llvm-qualified-auto,readability-qualified-auto,cppcoreguidelines-pro-type-vararg,hicpp-vararg)
 
-                    // note: at performs range check
-                    JSON_TRY
-                    {
-                        ptr = &ptr->at(static_cast<size_type>(array_index(reference_token)));
-                    }
-                    JSON_CATCH(std::invalid_argument&)
-                    {
-                        JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                    }
-                    break;
-                }
+        const bool is_negative = std::is_signed<NumberType>::value && !(x >= 0); // see issue #755
+        number_unsigned_t abs_value;
 
-                default:
-                    JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
-            }
+        unsigned int n_chars{};
+
+        if (is_negative)
+        {
+            *buffer_ptr = '-';
+            abs_value = remove_sign(static_cast<number_integer_t>(x));
+
+            // account one more byte for the minus sign
+            n_chars = 1 + count_digits(abs_value);
+        }
+        else
+        {
+            abs_value = static_cast<number_unsigned_t>(x);
+            n_chars = count_digits(abs_value);
         }
 
-        return *ptr;
+        // spare 1 byte for '\0'
+        JSON_ASSERT(n_chars < number_buffer.size() - 1);
+
+        // jump to the end to generate the string from backward
+        // so we later avoid reversing the result
+        buffer_ptr += n_chars;
+
+        // Fast int2ascii implementation inspired by "Fastware" talk by Andrei Alexandrescu
+        // See: https://www.youtube.com/watch?v=o4-CwDo2zpg
+        while (abs_value >= 100)
+        {
+            const auto digits_index = static_cast<unsigned>((abs_value % 100));
+            abs_value /= 100;
+            *(--buffer_ptr) = digits_to_99[digits_index][1];
+            *(--buffer_ptr) = digits_to_99[digits_index][0];
+        }
+
+        if (abs_value >= 10)
+        {
+            const auto digits_index = static_cast<unsigned>(abs_value);
+            *(--buffer_ptr) = digits_to_99[digits_index][1];
+            *(--buffer_ptr) = digits_to_99[digits_index][0];
+        }
+        else
+        {
+            *(--buffer_ptr) = static_cast<char>('0' + abs_value);
+        }
+
+        o->write_characters(number_buffer.data(), n_chars);
     }
 
     /*!
-    @brief return a const reference to the pointed to value
-
-    @param[in] ptr  a JSON value
+    @brief dump a floating-point number
 
-    @return const reference to the JSON value pointed to by the JSON
-    pointer
+    Dump a given floating-point number to output stream @a o. Works internally
+    with @a number_buffer.
 
-    @throw parse_error.106   if an array index begins with '0'
-    @throw parse_error.109   if an array index was not a number
-    @throw out_of_range.402  if the array index '-' is used
-    @throw out_of_range.404  if the JSON pointer can not be resolved
+    @param[in] x  floating-point number to dump
     */
-    const BasicJsonType& get_unchecked(const BasicJsonType* ptr) const
+    void dump_float(number_float_t x)
     {
-        using size_type = typename BasicJsonType::size_type;
-        for (const auto& reference_token : reference_tokens)
+        // NaN / inf
+        if (!std::isfinite(x))
         {
-            switch (ptr->m_type)
-            {
-                case detail::value_t::object:
-                {
-                    // use unchecked object access
-                    ptr = &ptr->operator[](reference_token);
-                    break;
-                }
+            o->write_characters("null", 4);
+            return;
+        }
 
-                case detail::value_t::array:
-                {
-                    if (JSON_UNLIKELY(reference_token == "-"))
-                    {
-                        // "-" cannot be used for const access
-                        JSON_THROW(detail::out_of_range::create(402,
-                                                                "array index '-' (" + std::to_string(ptr->m_value.array->size()) +
-                                                                ") is out of range"));
-                    }
+        // If number_float_t is an IEEE-754 single or double precision number,
+        // use the Grisu2 algorithm to produce short numbers which are
+        // guaranteed to round-trip, using strtof and strtod, resp.
+        //
+        // NB: The test below works if <long double> == <double>.
+        static constexpr bool is_ieee_single_or_double
+            = (std::numeric_limits<number_float_t>::is_iec559 && std::numeric_limits<number_float_t>::digits == 24 && std::numeric_limits<number_float_t>::max_exponent == 128) ||
+              (std::numeric_limits<number_float_t>::is_iec559 && std::numeric_limits<number_float_t>::digits == 53 && std::numeric_limits<number_float_t>::max_exponent == 1024);
 
-                    // error condition (cf. RFC 6901, Sect. 4)
-                    if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0'))
-                    {
-                        JSON_THROW(detail::parse_error::create(106, 0,
-                                                               "array index '" + reference_token +
-                                                               "' must not begin with '0'"));
-                    }
+        dump_float(x, std::integral_constant<bool, is_ieee_single_or_double>());
+    }
 
-                    // use unchecked array access
-                    JSON_TRY
-                    {
-                        ptr = &ptr->operator[](
-                            static_cast<size_type>(array_index(reference_token)));
-                    }
-                    JSON_CATCH(std::invalid_argument&)
-                    {
-                        JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                    }
-                    break;
-                }
+    void dump_float(number_float_t x, std::true_type /*is_ieee_single_or_double*/)
+    {
+        auto* begin = number_buffer.data();
+        auto* end = ::nlohmann::detail::to_chars(begin, begin + number_buffer.size(), x);
 
-                default:
-                    JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
+        o->write_characters(begin, static_cast<size_t>(end - begin));
+    }
+
+    void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/)
+    {
+        // get number of digits for a float -> text -> float round-trip
+        static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10;
+
+        // the actual conversion
+        // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
+        std::ptrdiff_t len = (std::snprintf)(number_buffer.data(), number_buffer.size(), "%.*g", d, x);
+
+        // negative value indicates an error
+        JSON_ASSERT(len > 0);
+        // check if buffer was large enough
+        JSON_ASSERT(static_cast<std::size_t>(len) < number_buffer.size());
+
+        // erase thousands separator
+        if (thousands_sep != '\0')
+        {
+            // NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::remove returns an iterator, see https://github.com/nlohmann/json/issues/3081
+            const auto end = std::remove(number_buffer.begin(), number_buffer.begin() + len, thousands_sep);
+            std::fill(end, number_buffer.end(), '\0');
+            JSON_ASSERT((end - number_buffer.begin()) <= len);
+            len = (end - number_buffer.begin());
+        }
+
+        // convert decimal point to '.'
+        if (decimal_point != '\0' && decimal_point != '.')
+        {
+            // NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::find returns an iterator, see https://github.com/nlohmann/json/issues/3081
+            const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
+            if (dec_pos != number_buffer.end())
+            {
+                *dec_pos = '.';
             }
         }
 
-        return *ptr;
+        o->write_characters(number_buffer.data(), static_cast<std::size_t>(len));
+
+        // determine if need to append ".0"
+        const bool value_is_int_like =
+            std::none_of(number_buffer.begin(), number_buffer.begin() + len + 1,
+                         [](char c)
+        {
+            return c == '.' || c == 'e';
+        });
+
+        if (value_is_int_like)
+        {
+            o->write_characters(".0", 2);
+        }
     }
 
     /*!
-    @throw parse_error.106   if an array index begins with '0'
-    @throw parse_error.109   if an array index was not a number
-    @throw out_of_range.402  if the array index '-' is used
-    @throw out_of_range.404  if the JSON pointer can not be resolved
+    @brief check whether a string is UTF-8 encoded
+
+    The function checks each byte of a string whether it is UTF-8 encoded. The
+    result of the check is stored in the @a state parameter. The function must
+    be called initially with state 0 (accept). State 1 means the string must
+    be rejected, because the current byte is not allowed. If the string is
+    completely processed, but the state is non-zero, the string ended
+    prematurely; that is, the last byte indicated more bytes should have
+    followed.
+
+    @param[in,out] state  the state of the decoding
+    @param[in,out] codep  codepoint (valid only if resulting state is UTF8_ACCEPT)
+    @param[in] byte       next byte to decode
+    @return               new state
+
+    @note The function has been edited: a std::array is used.
+
+    @copyright Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
+    @sa http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
     */
-    const BasicJsonType& get_checked(const BasicJsonType* ptr) const
+    static std::uint8_t decode(std::uint8_t& state, std::uint32_t& codep, const std::uint8_t byte) noexcept
     {
-        using size_type = typename BasicJsonType::size_type;
-        for (const auto& reference_token : reference_tokens)
+        static const std::array<std::uint8_t, 400> utf8d =
         {
-            switch (ptr->m_type)
             {
-                case detail::value_t::object:
-                {
-                    // note: at performs range check
-                    ptr = &ptr->at(reference_token);
-                    break;
-                }
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 00..1F
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20..3F
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 40..5F
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 60..7F
+                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 80..9F
+                7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // A0..BF
+                8, 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // C0..DF
+                0xA, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x4, 0x3, 0x3, // E0..EF
+                0xB, 0x6, 0x6, 0x6, 0x5, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, // F0..FF
+                0x0, 0x1, 0x2, 0x3, 0x5, 0x8, 0x7, 0x1, 0x1, 0x1, 0x4, 0x6, 0x1, 0x1, 0x1, 0x1, // s0..s0
+                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, // s1..s2
+                1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, // s3..s4
+                1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, // s5..s6
+                1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 // s7..s8
+            }
+        };
 
-                case detail::value_t::array:
-                {
-                    if (JSON_UNLIKELY(reference_token == "-"))
-                    {
-                        // "-" always fails the range check
-                        JSON_THROW(detail::out_of_range::create(402,
-                                                                "array index '-' (" + std::to_string(ptr->m_value.array->size()) +
-                                                                ") is out of range"));
-                    }
+        JSON_ASSERT(byte < utf8d.size());
+        const std::uint8_t type = utf8d[byte];
 
-                    // error condition (cf. RFC 6901, Sect. 4)
-                    if (JSON_UNLIKELY(reference_token.size() > 1 and reference_token[0] == '0'))
-                    {
-                        JSON_THROW(detail::parse_error::create(106, 0,
-                                                               "array index '" + reference_token +
-                                                               "' must not begin with '0'"));
-                    }
+        codep = (state != UTF8_ACCEPT)
+                ? (byte & 0x3fu) | (codep << 6u)
+                : (0xFFu >> type) & (byte);
 
-                    // note: at performs range check
-                    JSON_TRY
-                    {
-                        ptr = &ptr->at(static_cast<size_type>(array_index(reference_token)));
-                    }
-                    JSON_CATCH(std::invalid_argument&)
-                    {
-                        JSON_THROW(detail::parse_error::create(109, 0, "array index '" + reference_token + "' is not a number"));
-                    }
-                    break;
-                }
+        std::size_t index = 256u + static_cast<size_t>(state) * 16u + static_cast<size_t>(type);
+        JSON_ASSERT(index < 400);
+        state = utf8d[index];
+        return state;
+    }
 
-                default:
-                    JSON_THROW(detail::out_of_range::create(404, "unresolved reference token '" + reference_token + "'"));
-            }
-        }
+    /*
+     * Overload to make the compiler happy while it is instantiating
+     * dump_integer for number_unsigned_t.
+     * Must never be called.
+     */
+    number_unsigned_t remove_sign(number_unsigned_t x)
+    {
+        JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+        return x; // LCOV_EXCL_LINE
+    }
 
-        return *ptr;
+    /*
+     * Helper function for dump_integer
+     *
+     * This function takes a negative signed integer and returns its absolute
+     * value as unsigned integer. The plus/minus shuffling is necessary as we can
+     * not directly remove the sign of an arbitrary signed integer as the
+     * absolute values of INT_MIN and INT_MAX are usually not the same. See
+     * #1708 for details.
+     */
+    inline number_unsigned_t remove_sign(number_integer_t x) noexcept
+    {
+        JSON_ASSERT(x < 0 && x < (std::numeric_limits<number_integer_t>::max)()); // NOLINT(misc-redundant-expression)
+        return static_cast<number_unsigned_t>(-(x + 1)) + 1;
     }
 
-    /*!
-    @brief split the string input to reference tokens
+  private:
+    /// the output of the serializer
+    output_adapter_t<char> o = nullptr;
 
-    @note This function is only called by the json_pointer constructor.
-          All exceptions below are documented there.
+    /// a (hopefully) large enough character buffer
+    std::array<char, 64> number_buffer{{}};
 
-    @throw parse_error.107  if the pointer is not empty or begins with '/'
-    @throw parse_error.108  if character '~' is not followed by '0' or '1'
-    */
-    static std::vector<std::string> split(const std::string& reference_string)
-    {
-        std::vector<std::string> result;
+    /// the locale
+    const std::lconv* loc = nullptr;
+    /// the locale's thousand separator character
+    const char thousands_sep = '\0';
+    /// the locale's decimal point character
+    const char decimal_point = '\0';
 
-        // special case: empty reference string -> no reference tokens
-        if (reference_string.empty())
-        {
-            return result;
-        }
+    /// string buffer
+    std::array<char, 512> string_buffer{{}};
 
-        // check if nonempty reference string begins with slash
-        if (JSON_UNLIKELY(reference_string[0] != '/'))
-        {
-            JSON_THROW(detail::parse_error::create(107, 1,
-                                                   "JSON pointer must be empty or begin with '/' - was: '" +
-                                                   reference_string + "'"));
-        }
+    /// the indentation character
+    const char indent_char;
+    /// the indentation string
+    string_t indent_string;
 
-        // extract the reference tokens:
-        // - slash: position of the last read slash (or end of string)
-        // - start: position after the previous slash
-        for (
-            // search for the first slash after the first character
-            std::size_t slash = reference_string.find_first_of('/', 1),
-            // set the beginning of the first reference token
-            start = 1;
-            // we can stop if start == 0 (if slash == std::string::npos)
-            start != 0;
-            // set the beginning of the next reference token
-            // (will eventually be 0 if slash == std::string::npos)
-            start = (slash == std::string::npos) ? 0 : slash + 1,
-            // find next slash
-            slash = reference_string.find_first_of('/', start))
-        {
-            // use the text between the beginning of the reference token
-            // (start) and the last slash (slash).
-            auto reference_token = reference_string.substr(start, slash - start);
+    /// error_handler how to react on decoding errors
+    const error_handler_t error_handler;
+};
+}  // namespace detail
+}  // namespace nlohmann
 
-            // check reference tokens are properly escaped
-            for (std::size_t pos = reference_token.find_first_of('~');
-                    pos != std::string::npos;
-                    pos = reference_token.find_first_of('~', pos + 1))
-            {
-                assert(reference_token[pos] == '~');
+// #include <nlohmann/detail/value_t.hpp>
 
-                // ~ must be followed by 0 or 1
-                if (JSON_UNLIKELY(pos == reference_token.size() - 1 or
-                                  (reference_token[pos + 1] != '0' and
-                                   reference_token[pos + 1] != '1')))
-                {
-                    JSON_THROW(detail::parse_error::create(108, 0, "escape character '~' must be followed with '0' or '1'"));
-                }
-            }
+// #include <nlohmann/json_fwd.hpp>
 
-            // finally, store the reference token
-            unescape(reference_token);
-            result.push_back(reference_token);
-        }
+// #include <nlohmann/ordered_map.hpp>
 
-        return result;
-    }
 
-    /*!
-    @brief replace all occurrences of a substring by another string
+#include <functional> // less
+#include <initializer_list> // initializer_list
+#include <iterator> // input_iterator_tag, iterator_traits
+#include <memory> // allocator
+#include <stdexcept> // for out_of_range
+#include <type_traits> // enable_if, is_convertible
+#include <utility> // pair
+#include <vector> // vector
 
-    @param[in,out] s  the string to manipulate; changed so that all
-                   occurrences of @a f are replaced with @a t
-    @param[in]     f  the substring to replace with @a t
-    @param[in]     t  the string to replace @a f
+// #include <nlohmann/detail/macro_scope.hpp>
 
-    @pre The search string @a f must not be empty. **This precondition is
-    enforced with an assertion.**
 
-    @since version 2.0.0
-    */
-    static void replace_substring(std::string& s, const std::string& f,
-                                  const std::string& t)
+namespace nlohmann
+{
+
+/// ordered_map: a minimal map-like container that preserves insertion order
+/// for use within nlohmann::basic_json<ordered_map>
+template <class Key, class T, class IgnoredLess = std::less<Key>,
+          class Allocator = std::allocator<std::pair<const Key, T>>>
+                  struct ordered_map : std::vector<std::pair<const Key, T>, Allocator>
+{
+    using key_type = Key;
+    using mapped_type = T;
+    using Container = std::vector<std::pair<const Key, T>, Allocator>;
+    using typename Container::iterator;
+    using typename Container::const_iterator;
+    using typename Container::size_type;
+    using typename Container::value_type;
+
+    // Explicit constructors instead of `using Container::Container`
+    // otherwise older compilers choke on it (GCC <= 5.5, xcode <= 9.4)
+    ordered_map(const Allocator& alloc = Allocator()) : Container{alloc} {}
+    template <class It>
+    ordered_map(It first, It last, const Allocator& alloc = Allocator())
+        : Container{first, last, alloc} {}
+    ordered_map(std::initializer_list<T> init, const Allocator& alloc = Allocator() )
+        : Container{init, alloc} {}
+
+    std::pair<iterator, bool> emplace(const key_type& key, T&& t)
     {
-        assert(not f.empty());
-        for (auto pos = s.find(f);                // find first occurrence of f
-                pos != std::string::npos;         // make sure f was found
-                s.replace(pos, f.size(), t),      // replace with t, and
-                pos = s.find(f, pos + t.size()))  // find next occurrence of f
-        {}
+        for (auto it = this->begin(); it != this->end(); ++it)
+        {
+            if (it->first == key)
+            {
+                return {it, false};
+            }
+        }
+        Container::emplace_back(key, t);
+        return {--this->end(), true};
     }
 
-    /// escape "~" to "~0" and "/" to "~1"
-    static std::string escape(std::string s)
+    T& operator[](const Key& key)
     {
-        replace_substring(s, "~", "~0");
-        replace_substring(s, "/", "~1");
-        return s;
+        return emplace(key, T{}).first->second;
     }
 
-    /// unescape "~1" to tilde and "~0" to slash (order is important!)
-    static void unescape(std::string& s)
+    const T& operator[](const Key& key) const
     {
-        replace_substring(s, "~1", "/");
-        replace_substring(s, "~0", "~");
+        return at(key);
     }
 
-    /*!
-    @param[in] reference_string  the reference string to the current value
-    @param[in] value             the value to consider
-    @param[in,out] result        the result object to insert values to
-
-    @note Empty objects or arrays are flattened to `null`.
-    */
-    static void flatten(const std::string& reference_string,
-                        const BasicJsonType& value,
-                        BasicJsonType& result)
+    T& at(const Key& key)
     {
-        switch (value.m_type)
+        for (auto it = this->begin(); it != this->end(); ++it)
         {
-            case detail::value_t::array:
+            if (it->first == key)
             {
-                if (value.m_value.array->empty())
-                {
-                    // flatten empty array as null
-                    result[reference_string] = nullptr;
-                }
-                else
-                {
-                    // iterate array and use index as reference string
-                    for (std::size_t i = 0; i < value.m_value.array->size(); ++i)
-                    {
-                        flatten(reference_string + "/" + std::to_string(i),
-                                value.m_value.array->operator[](i), result);
-                    }
-                }
-                break;
+                return it->second;
             }
+        }
 
-            case detail::value_t::object:
-            {
-                if (value.m_value.object->empty())
-                {
-                    // flatten empty object as null
-                    result[reference_string] = nullptr;
-                }
-                else
-                {
-                    // iterate object and use keys as reference string
-                    for (const auto& element : *value.m_value.object)
-                    {
-                        flatten(reference_string + "/" + escape(element.first), element.second, result);
-                    }
-                }
-                break;
-            }
+        JSON_THROW(std::out_of_range("key not found"));
+    }
 
-            default:
+    const T& at(const Key& key) const
+    {
+        for (auto it = this->begin(); it != this->end(); ++it)
+        {
+            if (it->first == key)
             {
-                // add primitive value with its reference string
-                result[reference_string] = value;
-                break;
+                return it->second;
             }
         }
-    }
-
-    /*!
-    @param[in] value  flattened JSON
 
-    @return unflattened JSON
+        JSON_THROW(std::out_of_range("key not found"));
+    }
 
-    @throw parse_error.109 if array index is not a number
-    @throw type_error.314  if value is not an object
-    @throw type_error.315  if object values are not primitive
-    @throw type_error.313  if value cannot be unflattened
-    */
-    static BasicJsonType
-    unflatten(const BasicJsonType& value)
+    size_type erase(const Key& key)
+    {
+        for (auto it = this->begin(); it != this->end(); ++it)
+        {
+            if (it->first == key)
+            {
+                // Since we cannot move const Keys, re-construct them in place
+                for (auto next = it; ++next != this->end(); ++it)
+                {
+                    it->~value_type(); // Destroy but keep allocation
+                    new (&*it) value_type{std::move(*next)};
+                }
+                Container::pop_back();
+                return 1;
+            }
+        }
+        return 0;
+    }
+
+    iterator erase(iterator pos)
     {
-        if (JSON_UNLIKELY(not value.is_object()))
+        auto it = pos;
+
+        // Since we cannot move const Keys, re-construct them in place
+        for (auto next = it; ++next != this->end(); ++it)
         {
-            JSON_THROW(detail::type_error::create(314, "only objects can be unflattened"));
+            it->~value_type(); // Destroy but keep allocation
+            new (&*it) value_type{std::move(*next)};
         }
+        Container::pop_back();
+        return pos;
+    }
 
-        BasicJsonType result;
-
-        // iterate the JSON object values
-        for (const auto& element : *value.m_value.object)
+    size_type count(const Key& key) const
+    {
+        for (auto it = this->begin(); it != this->end(); ++it)
         {
-            if (JSON_UNLIKELY(not element.second.is_primitive()))
+            if (it->first == key)
             {
-                JSON_THROW(detail::type_error::create(315, "values in object must be primitive"));
+                return 1;
             }
-
-            // assign value to reference pointed to by JSON pointer; Note that if
-            // the JSON pointer is "" (i.e., points to the whole value), function
-            // get_and_create returns a reference to result itself. An assignment
-            // will then create a primitive value.
-            json_pointer(element.first).get_and_create(result) = element.second;
         }
-
-        return result;
+        return 0;
     }
 
-    friend bool operator==(json_pointer const& lhs,
-                           json_pointer const& rhs) noexcept
+    iterator find(const Key& key)
     {
-        return (lhs.reference_tokens == rhs.reference_tokens);
+        for (auto it = this->begin(); it != this->end(); ++it)
+        {
+            if (it->first == key)
+            {
+                return it;
+            }
+        }
+        return Container::end();
     }
 
-    friend bool operator!=(json_pointer const& lhs,
-                           json_pointer const& rhs) noexcept
+    const_iterator find(const Key& key) const
     {
-        return not (lhs == rhs);
+        for (auto it = this->begin(); it != this->end(); ++it)
+        {
+            if (it->first == key)
+            {
+                return it;
+            }
+        }
+        return Container::end();
     }
 
-    /// the reference tokens
-    std::vector<std::string> reference_tokens;
-};
-}  // namespace nlohmann
-
-// #include <nlohmann/adl_serializer.hpp>
-
-
-#include <utility>
-
-// #include <nlohmann/detail/conversions/from_json.hpp>
-
-// #include <nlohmann/detail/conversions/to_json.hpp>
-
-
-namespace nlohmann
-{
-
-template<typename, typename>
-struct adl_serializer
-{
-    /*!
-    @brief convert a JSON value to any value type
-
-    This function is usually called by the `get()` function of the
-    @ref basic_json class (either explicit or via conversion operators).
-
-    @param[in] j        JSON value to read from
-    @param[in,out] val  value to write to
-    */
-    template<typename BasicJsonType, typename ValueType>
-    static auto from_json(BasicJsonType&& j, ValueType& val) noexcept(
-        noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), val)))
-    -> decltype(::nlohmann::from_json(std::forward<BasicJsonType>(j), val), void())
+    std::pair<iterator, bool> insert( value_type&& value )
     {
-        ::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
+        return emplace(value.first, std::move(value.second));
     }
 
-    /*!
-    @brief convert any value type to a JSON value
+    std::pair<iterator, bool> insert( const value_type& value )
+    {
+        for (auto it = this->begin(); it != this->end(); ++it)
+        {
+            if (it->first == value.first)
+            {
+                return {it, false};
+            }
+        }
+        Container::push_back(value);
+        return {--this->end(), true};
+    }
 
-    This function is usually called by the constructors of the @ref basic_json
-    class.
+    template<typename InputIt>
+    using require_input_iter = typename std::enable_if<std::is_convertible<typename std::iterator_traits<InputIt>::iterator_category,
+            std::input_iterator_tag>::value>::type;
 
-    @param[in,out] j  JSON value to write to
-    @param[in] val    value to read from
-    */
-    template <typename BasicJsonType, typename ValueType>
-    static auto to_json(BasicJsonType& j, ValueType&& val) noexcept(
-        noexcept(::nlohmann::to_json(j, std::forward<ValueType>(val))))
-    -> decltype(::nlohmann::to_json(j, std::forward<ValueType>(val)), void())
+    template<typename InputIt, typename = require_input_iter<InputIt>>
+    void insert(InputIt first, InputIt last)
     {
-        ::nlohmann::to_json(j, std::forward<ValueType>(val));
+        for (auto it = first; it != last; ++it)
+        {
+            insert(*it);
+        }
     }
 };
 
 }  // namespace nlohmann
 
 
+#if defined(JSON_HAS_CPP_17)
+    #include <string_view>
+#endif
+
 /*!
 @brief namespace for Niels Lohmann
 @see https://github.com/nlohmann
@@ -12475,6 +17606,9 @@ default; will be used in @ref number_integer_t)
 `uint64_t` by default; will be used in @ref number_unsigned_t)
 @tparam NumberFloatType type for JSON floating-point numbers (`double` by
 default; will be used in @ref number_float_t)
+@tparam BinaryType type for packed binary data for compatibility with binary
+serialization formats (`std::vector<std::uint8_t>` by default; will be used in
+@ref binary_t)
 @tparam AllocatorType type of the allocator to use (`std::allocator` by
 default)
 @tparam JSONSerializer the serializer to resolve internal calls to `to_json()`
@@ -12529,42 +17663,58 @@ and `from_json()` (@ref adl_serializer by default)
 The invariants are checked by member function assert_invariant().
 
 @internal
-@note ObjectType trick from http://stackoverflow.com/a/9860911
+@note ObjectType trick from https://stackoverflow.com/a/9860911
 @endinternal
 
-@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange
-Format](http://rfc7159.net/rfc7159)
+@see [RFC 8259: The JavaScript Object Notation (JSON) Data Interchange
+Format](https://tools.ietf.org/html/rfc8259)
 
 @since version 1.0.0
 
 @nosubgrouping
 */
 NLOHMANN_BASIC_JSON_TPL_DECLARATION
-class basic_json
+class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-special-member-functions)
 {
   private:
     template<detail::value_t> friend struct detail::external_constructor;
     friend ::nlohmann::json_pointer<basic_json>;
-    friend ::nlohmann::detail::parser<basic_json>;
+
+    template<typename BasicJsonType, typename InputType>
+    friend class ::nlohmann::detail::parser;
     friend ::nlohmann::detail::serializer<basic_json>;
     template<typename BasicJsonType>
     friend class ::nlohmann::detail::iter_impl;
     template<typename BasicJsonType, typename CharType>
     friend class ::nlohmann::detail::binary_writer;
-    template<typename BasicJsonType, typename SAX>
+    template<typename BasicJsonType, typename InputType, typename SAX>
     friend class ::nlohmann::detail::binary_reader;
     template<typename BasicJsonType>
     friend class ::nlohmann::detail::json_sax_dom_parser;
     template<typename BasicJsonType>
     friend class ::nlohmann::detail::json_sax_dom_callback_parser;
+    friend class ::nlohmann::detail::exception;
 
     /// workaround type for MSVC
     using basic_json_t = NLOHMANN_BASIC_JSON_TPL;
 
+  JSON_PRIVATE_UNLESS_TESTED:
     // convenience aliases for types residing in namespace detail;
-    using lexer = ::nlohmann::detail::lexer<basic_json>;
-    using parser = ::nlohmann::detail::parser<basic_json>;
+    using lexer = ::nlohmann::detail::lexer_base<basic_json>;
+
+    template<typename InputAdapterType>
+    static ::nlohmann::detail::parser<basic_json, InputAdapterType> parser(
+        InputAdapterType adapter,
+        detail::parser_callback_t<basic_json>cb = nullptr,
+        const bool allow_exceptions = true,
+        const bool ignore_comments = false
+                                 )
+    {
+        return ::nlohmann::detail::parser<basic_json, InputAdapterType>(std::move(adapter),
+                std::move(cb), allow_exceptions, ignore_comments);
+    }
 
+  private:
     using primitive_iterator_t = ::nlohmann::detail::primitive_iterator_t;
     template<typename BasicJsonType>
     using internal_iterator = ::nlohmann::detail::internal_iterator<BasicJsonType>;
@@ -12577,9 +17727,11 @@ class basic_json
     template<typename CharType>
     using output_adapter_t = ::nlohmann::detail::output_adapter_t<CharType>;
 
-    using binary_reader = ::nlohmann::detail::binary_reader<basic_json>;
+    template<typename InputType>
+    using binary_reader = ::nlohmann::detail::binary_reader<basic_json, InputType>;
     template<typename CharType> using binary_writer = ::nlohmann::detail::binary_writer<basic_json, CharType>;
 
+  JSON_PRIVATE_UNLESS_TESTED:
     using serializer = ::nlohmann::detail::serializer<basic_json>;
 
   public:
@@ -12590,6 +17742,8 @@ class basic_json
     using json_serializer = JSONSerializer<T, SFINAE>;
     /// how to treat decoding errors
     using error_handler_t = detail::error_handler_t;
+    /// how to treat CBOR tags
+    using cbor_tag_handler_t = detail::cbor_tag_handler_t;
     /// helper type for initializer lists of basic_json values
     using initializer_list_t = std::initializer_list<detail::json_ref<basic_json>>;
 
@@ -12697,11 +17851,12 @@ class basic_json
 
     @since 2.1.0
     */
+    JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json meta()
     {
         basic_json result;
 
-        result["copyright"] = "(C) 2013-2017 Niels Lohmann";
+        result["copyright"] = "(C) 2013-2021 Niels Lohmann";
         result["name"] = "JSON for Modern C++";
         result["url"] = "https://github.com/nlohmann/json";
         result["version"]["string"] =
@@ -12773,7 +17928,7 @@ class basic_json
     /*!
     @brief a type for an object
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) describes JSON objects as follows:
     > An object is an unordered collection of zero or more name/value pairs,
     > where a name is a string and a value is a string, number, boolean, null,
     > object, or array.
@@ -12827,7 +17982,7 @@ class basic_json
 
     #### Limits
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) specifies:
     > An implementation may set limits on the maximum depth of nesting.
 
     In this class, the object's limit of nesting is not explicitly constrained.
@@ -12841,7 +17996,7 @@ class basic_json
     access to object values, a pointer of type `object_t*` must be
     dereferenced.
 
-    @sa @ref array_t -- type for an array value
+    @sa see @ref array_t -- type for an array value
 
     @since version 1.0.0
 
@@ -12850,7 +18005,7 @@ class basic_json
     name/value pairs in a different order than they were originally stored. In
     fact, keys will be traversed in alphabetical order as `std::map` with
     `std::less` is used by default. Please note this behavior conforms to [RFC
-    7159](http://rfc7159.net/rfc7159), because any order implements the
+    8259](https://tools.ietf.org/html/rfc8259), because any order implements the
     specified "unordered" nature of JSON objects.
     */
     using object_t = ObjectType<StringType,
@@ -12862,7 +18017,7 @@ class basic_json
     /*!
     @brief a type for an array
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) describes JSON arrays as follows:
     > An array is an ordered sequence of zero or more values.
 
     To store objects in C++, a type is defined by the template parameters
@@ -12886,7 +18041,7 @@ class basic_json
 
     #### Limits
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) specifies:
     > An implementation may set limits on the maximum depth of nesting.
 
     In this class, the array's limit of nesting is not explicitly constrained.
@@ -12899,7 +18054,7 @@ class basic_json
     Arrays are stored as pointers in a @ref basic_json type. That is, for any
     access to array values, a pointer of type `array_t*` must be dereferenced.
 
-    @sa @ref object_t -- type for an object value
+    @sa see @ref object_t -- type for an object value
 
     @since version 1.0.0
     */
@@ -12908,7 +18063,7 @@ class basic_json
     /*!
     @brief a type for a string
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) describes JSON strings as follows:
     > A string is a sequence of zero or more Unicode characters.
 
     To store objects in C++, a type is defined by the template parameter
@@ -12935,7 +18090,7 @@ class basic_json
 
     #### String comparison
 
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) states:
     > Software implementations are typically required to test names of object
     > members for equality. Implementations that transform the textual
     > representation into sequences of Unicode code units and then perform the
@@ -12961,7 +18116,7 @@ class basic_json
     /*!
     @brief a type for a boolean
 
-    [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) implicitly describes a boolean as a
     type which differentiates the two literals `true` and `false`.
 
     To store objects in C++, a type is defined by the template parameter @a
@@ -12987,7 +18142,7 @@ class basic_json
     /*!
     @brief a type for a number (integer)
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) describes numbers as follows:
     > The representation of numbers is similar to that used in most
     > programming languages. A number is represented in base 10 using decimal
     > digits. It contains an integer component that may be prefixed with an
@@ -13025,7 +18180,7 @@ class basic_json
 
     #### Limits
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) specifies:
     > An implementation may set limits on the range and precision of numbers.
 
     When the default type is used, the maximal integer number that can be
@@ -13036,7 +18191,7 @@ class basic_json
     will be automatically be stored as @ref number_unsigned_t or @ref
     number_float_t.
 
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
     > Note that when such software is used, numbers that are integers and are
     > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
     > that implementations will agree exactly on their numeric values.
@@ -13048,9 +18203,9 @@ class basic_json
 
     Integer number values are stored directly inside a @ref basic_json type.
 
-    @sa @ref number_float_t -- type for number values (floating-point)
+    @sa see @ref number_float_t -- type for number values (floating-point)
 
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+    @sa see @ref number_unsigned_t -- type for number values (unsigned integer)
 
     @since version 1.0.0
     */
@@ -13059,7 +18214,7 @@ class basic_json
     /*!
     @brief a type for a number (unsigned)
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) describes numbers as follows:
     > The representation of numbers is similar to that used in most
     > programming languages. A number is represented in base 10 using decimal
     > digits. It contains an integer component that may be prefixed with an
@@ -13097,7 +18252,7 @@ class basic_json
 
     #### Limits
 
-    [RFC 7159](http://rfc7159.net/rfc7159) specifies:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) specifies:
     > An implementation may set limits on the range and precision of numbers.
 
     When the default type is used, the maximal integer number that can be
@@ -13107,7 +18262,7 @@ class basic_json
     deserialization, too large or small integer numbers will be automatically
     be stored as @ref number_integer_t or @ref number_float_t.
 
-    [RFC 7159](http://rfc7159.net/rfc7159) further states:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
     > Note that when such software is used, numbers that are integers and are
     > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense
     > that implementations will agree exactly on their numeric values.
@@ -13120,8 +18275,8 @@ class basic_json
 
     Integer number values are stored directly inside a @ref basic_json type.
 
-    @sa @ref number_float_t -- type for number values (floating-point)
-    @sa @ref number_integer_t -- type for number values (integer)
+    @sa see @ref number_float_t -- type for number values (floating-point)
+    @sa see @ref number_integer_t -- type for number values (integer)
 
     @since version 2.0.0
     */
@@ -13130,7 +18285,7 @@ class basic_json
     /*!
     @brief a type for a number (floating-point)
 
-    [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) describes numbers as follows:
     > The representation of numbers is similar to that used in most
     > programming languages. A number is represented in base 10 using decimal
     > digits. It contains an integer component that may be prefixed with an
@@ -13168,7 +18323,7 @@ class basic_json
 
     #### Limits
 
-    [RFC 7159](http://rfc7159.net/rfc7159) states:
+    [RFC 8259](https://tools.ietf.org/html/rfc8259) states:
     > This specification allows implementations to set limits on the range and
     > precision of numbers accepted. Since software that implements IEEE
     > 754-2008 binary64 (double precision) numbers is generally available and
@@ -13187,39 +18342,111 @@ class basic_json
     Floating-point number values are stored directly inside a @ref basic_json
     type.
 
-    @sa @ref number_integer_t -- type for number values (integer)
+    @sa see @ref number_integer_t -- type for number values (integer)
 
-    @sa @ref number_unsigned_t -- type for number values (unsigned integer)
+    @sa see @ref number_unsigned_t -- type for number values (unsigned integer)
 
     @since version 1.0.0
     */
     using number_float_t = NumberFloatType;
 
+    /*!
+    @brief a type for a packed binary type
+
+    This type is a type designed to carry binary data that appears in various
+    serialized formats, such as CBOR's Major Type 2, MessagePack's bin, and
+    BSON's generic binary subtype. This type is NOT a part of standard JSON and
+    exists solely for compatibility with these binary types. As such, it is
+    simply defined as an ordered sequence of zero or more byte values.
+
+    Additionally, as an implementation detail, the subtype of the binary data is
+    carried around as a `std::uint8_t`, which is compatible with both of the
+    binary data formats that use binary subtyping, (though the specific
+    numbering is incompatible with each other, and it is up to the user to
+    translate between them).
+
+    [CBOR's RFC 7049](https://tools.ietf.org/html/rfc7049) describes this type
+    as:
+    > Major type 2: a byte string. The string's length in bytes is represented
+    > following the rules for positive integers (major type 0).
+
+    [MessagePack's documentation on the bin type
+    family](https://github.com/msgpack/msgpack/blob/master/spec.md#bin-format-family)
+    describes this type as:
+    > Bin format family stores an byte array in 2, 3, or 5 bytes of extra bytes
+    > in addition to the size of the byte array.
+
+    [BSON's specifications](http://bsonspec.org/spec.html) describe several
+    binary types; however, this type is intended to represent the generic binary
+    type which has the description:
+    > Generic binary subtype - This is the most commonly used binary subtype and
+    > should be the 'default' for drivers and tools.
+
+    None of these impose any limitations on the internal representation other
+    than the basic unit of storage be some type of array whose parts are
+    decomposable into bytes.
+
+    The default representation of this binary format is a
+    `std::vector<std::uint8_t>`, which is a very common way to represent a byte
+    array in modern C++.
+
+    #### Default type
+
+    The default values for @a BinaryType is `std::vector<std::uint8_t>`
+
+    #### Storage
+
+    Binary Arrays are stored as pointers in a @ref basic_json type. That is,
+    for any access to array values, a pointer of the type `binary_t*` must be
+    dereferenced.
+
+    #### Notes on subtypes
+
+    - CBOR
+       - Binary values are represented as byte strings. Subtypes are serialized
+         as tagged values.
+    - MessagePack
+       - If a subtype is given and the binary array contains exactly 1, 2, 4, 8,
+         or 16 elements, the fixext family (fixext1, fixext2, fixext4, fixext8)
+         is used. For other sizes, the ext family (ext8, ext16, ext32) is used.
+         The subtype is then added as singed 8-bit integer.
+       - If no subtype is given, the bin family (bin8, bin16, bin32) is used.
+    - BSON
+       - If a subtype is given, it is used and added as unsigned 8-bit integer.
+       - If no subtype is given, the generic binary subtype 0x00 is used.
+
+    @sa see @ref binary -- create a binary array
+
+    @since version 3.8.0
+    */
+    using binary_t = nlohmann::byte_container_with_subtype<BinaryType>;
     /// @}
 
   private:
 
     /// helper for exception-safe object creation
     template<typename T, typename... Args>
+    JSON_HEDLEY_RETURNS_NON_NULL
     static T* create(Args&& ... args)
     {
         AllocatorType<T> alloc;
         using AllocatorTraits = std::allocator_traits<AllocatorType<T>>;
 
-        auto deleter = [&](T * object)
+        auto deleter = [&](T * obj)
         {
-            AllocatorTraits::deallocate(alloc, object, 1);
+            AllocatorTraits::deallocate(alloc, obj, 1);
         };
-        std::unique_ptr<T, decltype(deleter)> object(AllocatorTraits::allocate(alloc, 1), deleter);
-        AllocatorTraits::construct(alloc, object.get(), std::forward<Args>(args)...);
-        assert(object != nullptr);
-        return object.release();
+        std::unique_ptr<T, decltype(deleter)> obj(AllocatorTraits::allocate(alloc, 1), deleter);
+        AllocatorTraits::construct(alloc, obj.get(), std::forward<Args>(args)...);
+        JSON_ASSERT(obj != nullptr);
+        return obj.release();
     }
 
     ////////////////////////
     // JSON value storage //
     ////////////////////////
 
+  JSON_PRIVATE_UNLESS_TESTED:
     /*!
     @brief a JSON value
 
@@ -13236,6 +18463,7 @@ class basic_json
     number    | number_integer  | @ref number_integer_t
     number    | number_unsigned | @ref number_unsigned_t
     number    | number_float    | @ref number_float_t
+    binary    | binary          | pointer to @ref binary_t
     null      | null            | *no value is stored*
 
     @note Variable-length types (objects, arrays, and strings) are stored as
@@ -13252,6 +18480,8 @@ class basic_json
         array_t* array;
         /// string (stored with pointer to save storage)
         string_t* string;
+        /// binary (stored with pointer to save storage)
+        binary_t* binary;
         /// boolean
         boolean_t boolean;
         /// number (integer)
@@ -13294,6 +18524,12 @@ class basic_json
                     break;
                 }
 
+                case value_t::binary:
+                {
+                    binary = create<binary_t>();
+                    break;
+                }
+
                 case value_t::boolean:
                 {
                     boolean = boolean_t(false);
@@ -13324,12 +18560,13 @@ class basic_json
                     break;
                 }
 
+                case value_t::discarded:
                 default:
                 {
                     object = nullptr;  // silence warning, see #821
-                    if (JSON_UNLIKELY(t == value_t::null))
+                    if (JSON_HEDLEY_UNLIKELY(t == value_t::null))
                     {
-                        JSON_THROW(other_error::create(500, "961c151d2e87f2686a955a9be24d316f1362bf21 3.5.0")); // LCOV_EXCL_LINE
+                        JSON_THROW(other_error::create(500, "961c151d2e87f2686a955a9be24d316f1362bf21 3.10.4", basic_json())); // LCOV_EXCL_LINE
                     }
                     break;
                 }
@@ -13372,8 +18609,81 @@ class basic_json
             array = create<array_t>(std::move(value));
         }
 
-        void destroy(value_t t) noexcept
+        /// constructor for binary arrays
+        json_value(const typename binary_t::container_type& value)
+        {
+            binary = create<binary_t>(value);
+        }
+
+        /// constructor for rvalue binary arrays
+        json_value(typename binary_t::container_type&& value)
+        {
+            binary = create<binary_t>(std::move(value));
+        }
+
+        /// constructor for binary arrays (internal type)
+        json_value(const binary_t& value)
+        {
+            binary = create<binary_t>(value);
+        }
+
+        /// constructor for rvalue binary arrays (internal type)
+        json_value(binary_t&& value)
         {
+            binary = create<binary_t>(std::move(value));
+        }
+
+        void destroy(value_t t)
+        {
+            if (t == value_t::array || t == value_t::object)
+            {
+                // flatten the current json_value to a heap-allocated stack
+                std::vector<basic_json> stack;
+
+                // move the top-level items to stack
+                if (t == value_t::array)
+                {
+                    stack.reserve(array->size());
+                    std::move(array->begin(), array->end(), std::back_inserter(stack));
+                }
+                else
+                {
+                    stack.reserve(object->size());
+                    for (auto&& it : *object)
+                    {
+                        stack.push_back(std::move(it.second));
+                    }
+                }
+
+                while (!stack.empty())
+                {
+                    // move the last item to local variable to be processed
+                    basic_json current_item(std::move(stack.back()));
+                    stack.pop_back();
+
+                    // if current_item is array/object, move
+                    // its children to the stack to be processed later
+                    if (current_item.is_array())
+                    {
+                        std::move(current_item.m_value.array->begin(), current_item.m_value.array->end(), std::back_inserter(stack));
+
+                        current_item.m_value.array->clear();
+                    }
+                    else if (current_item.is_object())
+                    {
+                        for (auto&& it : *current_item.m_value.object)
+                        {
+                            stack.push_back(std::move(it.second));
+                        }
+
+                        current_item.m_value.object->clear();
+                    }
+
+                    // it's now safe that current_item get destructed
+                    // since it doesn't have any children
+                }
+            }
+
             switch (t)
             {
                 case value_t::object:
@@ -13400,6 +18710,20 @@ class basic_json
                     break;
                 }
 
+                case value_t::binary:
+                {
+                    AllocatorType<binary_t> alloc;
+                    std::allocator_traits<decltype(alloc)>::destroy(alloc, binary);
+                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, binary, 1);
+                    break;
+                }
+
+                case value_t::null:
+                case value_t::boolean:
+                case value_t::number_integer:
+                case value_t::number_unsigned:
+                case value_t::number_float:
+                case value_t::discarded:
                 default:
                 {
                     break;
@@ -13408,6 +18732,7 @@ class basic_json
         }
     };
 
+  private:
     /*!
     @brief checks the class invariants
 
@@ -13416,12 +18741,123 @@ class basic_json
     invariant. Furthermore, it has to be called each time the type of a JSON
     value is changed, because the invariant expresses a relationship between
     @a m_type and @a m_value.
+
+    Furthermore, the parent relation is checked for arrays and objects: If
+    @a check_parents true and the value is an array or object, then the
+    container's elements must have the current value as parent.
+
+    @param[in] check_parents  whether the parent relation should be checked.
+               The value is true by default and should only be set to false
+               during destruction of objects when the invariant does not
+               need to hold.
     */
-    void assert_invariant() const noexcept
+    void assert_invariant(bool check_parents = true) const noexcept
+    {
+        JSON_ASSERT(m_type != value_t::object || m_value.object != nullptr);
+        JSON_ASSERT(m_type != value_t::array || m_value.array != nullptr);
+        JSON_ASSERT(m_type != value_t::string || m_value.string != nullptr);
+        JSON_ASSERT(m_type != value_t::binary || m_value.binary != nullptr);
+
+#if JSON_DIAGNOSTICS
+        JSON_TRY
+        {
+            // cppcheck-suppress assertWithSideEffect
+            JSON_ASSERT(!check_parents || !is_structured() || std::all_of(begin(), end(), [this](const basic_json & j)
+            {
+                return j.m_parent == this;
+            }));
+        }
+        JSON_CATCH(...) {} // LCOV_EXCL_LINE
+#endif
+        static_cast<void>(check_parents);
+    }
+
+    void set_parents()
+    {
+#if JSON_DIAGNOSTICS
+        switch (m_type)
+        {
+            case value_t::array:
+            {
+                for (auto& element : *m_value.array)
+                {
+                    element.m_parent = this;
+                }
+                break;
+            }
+
+            case value_t::object:
+            {
+                for (auto& element : *m_value.object)
+                {
+                    element.second.m_parent = this;
+                }
+                break;
+            }
+
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+                break;
+        }
+#endif
+    }
+
+    iterator set_parents(iterator it, typename iterator::difference_type count)
+    {
+#if JSON_DIAGNOSTICS
+        for (typename iterator::difference_type i = 0; i < count; ++i)
+        {
+            (it + i)->m_parent = this;
+        }
+#else
+        static_cast<void>(count);
+#endif
+        return it;
+    }
+
+    reference set_parent(reference j, std::size_t old_capacity = std::size_t(-1))
     {
-        assert(m_type != value_t::object or m_value.object != nullptr);
-        assert(m_type != value_t::array or m_value.array != nullptr);
-        assert(m_type != value_t::string or m_value.string != nullptr);
+#if JSON_DIAGNOSTICS
+        if (old_capacity != std::size_t(-1))
+        {
+            // see https://github.com/nlohmann/json/issues/2838
+            JSON_ASSERT(type() == value_t::array);
+            if (JSON_HEDLEY_UNLIKELY(m_value.array->capacity() != old_capacity))
+            {
+                // capacity has changed: update all parents
+                set_parents();
+                return j;
+            }
+        }
+
+        // ordered_json uses a vector internally, so pointers could have
+        // been invalidated; see https://github.com/nlohmann/json/issues/2962
+#ifdef JSON_HEDLEY_MSVC_VERSION
+#pragma warning(push )
+#pragma warning(disable : 4127) // ignore warning to replace if with if constexpr
+#endif
+        if (detail::is_ordered_map<object_t>::value)
+        {
+            set_parents();
+            return j;
+        }
+#ifdef JSON_HEDLEY_MSVC_VERSION
+#pragma warning( pop )
+#endif
+
+        j.m_parent = this;
+#else
+        static_cast<void>(j);
+        static_cast<void>(old_capacity);
+#endif
+        return j;
     }
 
   public:
@@ -13442,9 +18878,9 @@ class basic_json
 
     @image html callback_events.png "Example when certain parse events are triggered"
 
-    @sa @ref parser_callback_t for more information and examples
+    @sa see @ref parser_callback_t for more information and examples
     */
-    using parse_event_t = typename parser::parse_event_t;
+    using parse_event_t = detail::parse_event_t;
 
     /*!
     @brief per-element parser callback type
@@ -13491,11 +18927,11 @@ class basic_json
     should be kept (`true`) or not (`false`). In the latter case, it is either
     skipped completely or replaced by an empty discarded object.
 
-    @sa @ref parse for examples
+    @sa see @ref parse for examples
 
     @since version 1.0.0
     */
-    using parser_callback_t = typename parser::parser_callback_t;
+    using parser_callback_t = detail::parser_callback_t<basic_json>;
 
     //////////////////
     // constructors //
@@ -13520,6 +18956,7 @@ class basic_json
     number      | `0`
     object      | `{}`
     array       | `[]`
+    binary      | empty array
 
     @param[in] v  the type of the value to create
 
@@ -13531,7 +18968,7 @@ class basic_json
     @liveexample{The following code shows the constructor for different @ref
     value_t values,basic_json__value_t}
 
-    @sa @ref clear() -- restores the postcondition of this constructor
+    @sa see @ref clear() -- restores the postcondition of this constructor
 
     @since version 1.0.0
     */
@@ -13591,6 +19028,12 @@ class basic_json
       @ref number_float_t, and all convertible number types such as `int`,
       `size_t`, `int64_t`, `float` or `double` can be used.
     - **boolean**: @ref boolean_t / `bool` can be used.
+    - **binary**: @ref binary_t / `std::vector<std::uint8_t>` may be used,
+      unfortunately because string literals cannot be distinguished from binary
+      character arrays by the C++ type system, all types compatible with `const
+      char*` will be directed to the string constructor instead.  This is both
+      for backwards compatibility, and due to the fact that a binary type is not
+      a standard JSON type.
 
     See the examples below.
 
@@ -13601,8 +19044,7 @@ class basic_json
     - @a CompatibleType is not a different @ref basic_json type (i.e. with different template arguments)
     - @a CompatibleType is not a @ref basic_json nested type (e.g.,
          @ref json_pointer, @ref iterator, etc ...)
-    - @ref @ref json_serializer<U> has a
-         `to_json(basic_json_t&, CompatibleType&&)` method
+    - `json_serializer<U>` has a `to_json(basic_json_t&, CompatibleType&&)` method
 
     @tparam U = `uncvref_t<CompatibleType>`
 
@@ -13622,15 +19064,16 @@ class basic_json
 
     @since version 2.1.0
     */
-    template <typename CompatibleType,
-              typename U = detail::uncvref_t<CompatibleType>,
-              detail::enable_if_t<
-                  not detail::is_basic_json<U>::value and detail::is_compatible_type<basic_json_t, U>::value, int> = 0>
-    basic_json(CompatibleType && val) noexcept(noexcept(
+    template < typename CompatibleType,
+               typename U = detail::uncvref_t<CompatibleType>,
+               detail::enable_if_t <
+                   !detail::is_basic_json<U>::value && detail::is_compatible_type<basic_json_t, U>::value, int > = 0 >
+    basic_json(CompatibleType && val) noexcept(noexcept( // NOLINT(bugprone-forwarding-reference-overload,bugprone-exception-escape)
                 JSONSerializer<U>::to_json(std::declval<basic_json_t&>(),
                                            std::forward<CompatibleType>(val))))
     {
         JSONSerializer<U>::to_json(*this, std::forward<CompatibleType>(val));
+        set_parents();
         assert_invariant();
     }
 
@@ -13660,9 +19103,9 @@ class basic_json
 
     @since version 3.2.0
     */
-    template <typename BasicJsonType,
-              detail::enable_if_t<
-                  detail::is_basic_json<BasicJsonType>::value and not std::is_same<basic_json, BasicJsonType>::value, int> = 0>
+    template < typename BasicJsonType,
+               detail::enable_if_t <
+                   detail::is_basic_json<BasicJsonType>::value&& !std::is_same<basic_json, BasicJsonType>::value, int > = 0 >
     basic_json(const BasicJsonType& val)
     {
         using other_boolean_t = typename BasicJsonType::boolean_t;
@@ -13672,6 +19115,7 @@ class basic_json
         using other_string_t = typename BasicJsonType::string_t;
         using other_object_t = typename BasicJsonType::object_t;
         using other_array_t = typename BasicJsonType::array_t;
+        using other_binary_t = typename BasicJsonType::binary_t;
 
         switch (val.type())
         {
@@ -13696,13 +19140,19 @@ class basic_json
             case value_t::array:
                 JSONSerializer<other_array_t>::to_json(*this, val.template get_ref<const other_array_t&>());
                 break;
+            case value_t::binary:
+                JSONSerializer<other_binary_t>::to_json(*this, val.template get_ref<const other_binary_t&>());
+                break;
             case value_t::null:
                 *this = nullptr;
                 break;
             case value_t::discarded:
                 m_type = value_t::discarded;
                 break;
+            default:            // LCOV_EXCL_LINE
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
         }
+        set_parents();
         assert_invariant();
     }
 
@@ -13773,9 +19223,9 @@ class basic_json
     @liveexample{The example below shows how JSON values are created from
     initializer lists.,basic_json__list_init_t}
 
-    @sa @ref array(initializer_list_t) -- create a JSON array
+    @sa see @ref array(initializer_list_t) -- create a JSON array
     value from an initializer list
-    @sa @ref object(initializer_list_t) -- create a JSON object
+    @sa see @ref object(initializer_list_t) -- create a JSON object
     value from an initializer list
 
     @since version 1.0.0
@@ -13789,11 +19239,11 @@ class basic_json
         bool is_an_object = std::all_of(init.begin(), init.end(),
                                         [](const detail::json_ref<basic_json>& element_ref)
         {
-            return (element_ref->is_array() and element_ref->size() == 2 and (*element_ref)[0].is_string());
+            return element_ref->is_array() && element_ref->size() == 2 && (*element_ref)[0].is_string();
         });
 
         // adjust type if type deduction is not wanted
-        if (not type_deduction)
+        if (!type_deduction)
         {
             // if array is wanted, do not create an object though possible
             if (manual_type == value_t::array)
@@ -13802,9 +19252,9 @@ class basic_json
             }
 
             // if object is wanted but impossible, throw an exception
-            if (JSON_UNLIKELY(manual_type == value_t::object and not is_an_object))
+            if (JSON_HEDLEY_UNLIKELY(manual_type == value_t::object && !is_an_object))
             {
-                JSON_THROW(type_error::create(301, "cannot create object from initializer list"));
+                JSON_THROW(type_error::create(301, "cannot create object from initializer list", basic_json()));
             }
         }
 
@@ -13814,13 +19264,13 @@ class basic_json
             m_type = value_t::object;
             m_value = value_t::object;
 
-            std::for_each(init.begin(), init.end(), [this](const detail::json_ref<basic_json>& element_ref)
+            for (auto& element_ref : init)
             {
                 auto element = element_ref.moved_or_copied();
                 m_value.object->emplace(
                     std::move(*((*element.m_value.array)[0].m_value.string)),
                     std::move((*element.m_value.array)[1]));
-            });
+            }
         }
         else
         {
@@ -13829,7 +19279,101 @@ class basic_json
             m_value.array = create<array_t>(init.begin(), init.end());
         }
 
-        assert_invariant();
+        set_parents();
+        assert_invariant();
+    }
+
+    /*!
+    @brief explicitly create a binary array (without subtype)
+
+    Creates a JSON binary array value from a given binary container. Binary
+    values are part of various binary formats, such as CBOR, MessagePack, and
+    BSON. This constructor is used to create a value for serialization to those
+    formats.
+
+    @note Note, this function exists because of the difficulty in correctly
+    specifying the correct template overload in the standard value ctor, as both
+    JSON arrays and JSON binary arrays are backed with some form of a
+    `std::vector`. Because JSON binary arrays are a non-standard extension it
+    was decided that it would be best to prevent automatic initialization of a
+    binary array type, for backwards compatibility and so it does not happen on
+    accident.
+
+    @param[in] init container containing bytes to use as binary type
+
+    @return JSON binary array value
+
+    @complexity Linear in the size of @a init.
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
+
+    @since version 3.8.0
+    */
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json binary(const typename binary_t::container_type& init)
+    {
+        auto res = basic_json();
+        res.m_type = value_t::binary;
+        res.m_value = init;
+        return res;
+    }
+
+    /*!
+    @brief explicitly create a binary array (with subtype)
+
+    Creates a JSON binary array value from a given binary container. Binary
+    values are part of various binary formats, such as CBOR, MessagePack, and
+    BSON. This constructor is used to create a value for serialization to those
+    formats.
+
+    @note Note, this function exists because of the difficulty in correctly
+    specifying the correct template overload in the standard value ctor, as both
+    JSON arrays and JSON binary arrays are backed with some form of a
+    `std::vector`. Because JSON binary arrays are a non-standard extension it
+    was decided that it would be best to prevent automatic initialization of a
+    binary array type, for backwards compatibility and so it does not happen on
+    accident.
+
+    @param[in] init container containing bytes to use as binary type
+    @param[in] subtype subtype to use in MessagePack and BSON
+
+    @return JSON binary array value
+
+    @complexity Linear in the size of @a init.
+
+    @exceptionsafety Strong guarantee: if an exception is thrown, there are no
+    changes to any JSON value.
+
+    @since version 3.8.0
+    */
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json binary(const typename binary_t::container_type& init, typename binary_t::subtype_type subtype)
+    {
+        auto res = basic_json();
+        res.m_type = value_t::binary;
+        res.m_value = binary_t(init, subtype);
+        return res;
+    }
+
+    /// @copydoc binary(const typename binary_t::container_type&)
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json binary(typename binary_t::container_type&& init)
+    {
+        auto res = basic_json();
+        res.m_type = value_t::binary;
+        res.m_value = std::move(init);
+        return res;
+    }
+
+    /// @copydoc binary(const typename binary_t::container_type&, typename binary_t::subtype_type)
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json binary(typename binary_t::container_type&& init, typename binary_t::subtype_type subtype)
+    {
+        auto res = basic_json();
+        res.m_type = value_t::binary;
+        res.m_value = binary_t(std::move(init), subtype);
+        return res;
     }
 
     /*!
@@ -13862,13 +19406,14 @@ class basic_json
     @liveexample{The following code shows an example for the `array`
     function.,array}
 
-    @sa @ref basic_json(initializer_list_t, bool, value_t) --
+    @sa see @ref basic_json(initializer_list_t, bool, value_t) --
     create a JSON value from an initializer list
-    @sa @ref object(initializer_list_t) -- create a JSON object
+    @sa see @ref object(initializer_list_t) -- create a JSON object
     value from an initializer list
 
     @since version 1.0.0
     */
+    JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json array(initializer_list_t init = {})
     {
         return basic_json(init, false, value_t::array);
@@ -13905,13 +19450,14 @@ class basic_json
     @liveexample{The following code shows an example for the `object`
     function.,object}
 
-    @sa @ref basic_json(initializer_list_t, bool, value_t) --
+    @sa see @ref basic_json(initializer_list_t, bool, value_t) --
     create a JSON value from an initializer list
-    @sa @ref array(initializer_list_t) -- create a JSON array
+    @sa see @ref array(initializer_list_t) -- create a JSON array
     value from an initializer list
 
     @since version 1.0.0
     */
+    JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json object(initializer_list_t init = {})
     {
         return basic_json(init, false, value_t::object);
@@ -13943,6 +19489,7 @@ class basic_json
         : m_type(value_t::array)
     {
         m_value.array = create<array_t>(cnt, val);
+        set_parents();
         assert_invariant();
     }
 
@@ -14001,18 +19548,18 @@ class basic_json
 
     @since version 1.0.0
     */
-    template<class InputIT, typename std::enable_if<
-                 std::is_same<InputIT, typename basic_json_t::iterator>::value or
-                 std::is_same<InputIT, typename basic_json_t::const_iterator>::value, int>::type = 0>
+    template < class InputIT, typename std::enable_if <
+                   std::is_same<InputIT, typename basic_json_t::iterator>::value ||
+                   std::is_same<InputIT, typename basic_json_t::const_iterator>::value, int >::type = 0 >
     basic_json(InputIT first, InputIT last)
     {
-        assert(first.m_object != nullptr);
-        assert(last.m_object != nullptr);
+        JSON_ASSERT(first.m_object != nullptr);
+        JSON_ASSERT(last.m_object != nullptr);
 
         // make sure iterator fits the current value
-        if (JSON_UNLIKELY(first.m_object != last.m_object))
+        if (JSON_HEDLEY_UNLIKELY(first.m_object != last.m_object))
         {
-            JSON_THROW(invalid_iterator::create(201, "iterators are not compatible"));
+            JSON_THROW(invalid_iterator::create(201, "iterators are not compatible", basic_json()));
         }
 
         // copy type from first iterator
@@ -14027,14 +19574,19 @@ class basic_json
             case value_t::number_unsigned:
             case value_t::string:
             {
-                if (JSON_UNLIKELY(not first.m_it.primitive_iterator.is_begin()
-                                  or not last.m_it.primitive_iterator.is_end()))
+                if (JSON_HEDLEY_UNLIKELY(!first.m_it.primitive_iterator.is_begin()
+                                         || !last.m_it.primitive_iterator.is_end()))
                 {
-                    JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
+                    JSON_THROW(invalid_iterator::create(204, "iterators out of range", *first.m_object));
                 }
                 break;
             }
 
+            case value_t::null:
+            case value_t::object:
+            case value_t::array:
+            case value_t::binary:
+            case value_t::discarded:
             default:
                 break;
         }
@@ -14085,11 +19637,19 @@ class basic_json
                 break;
             }
 
+            case value_t::binary:
+            {
+                m_value = *first.m_object->m_value.binary;
+                break;
+            }
+
+            case value_t::null:
+            case value_t::discarded:
             default:
-                JSON_THROW(invalid_iterator::create(206, "cannot construct with iterators from " +
-                                                    std::string(first.m_object->type_name())));
+                JSON_THROW(invalid_iterator::create(206, "cannot construct with iterators from " + std::string(first.m_object->type_name()), *first.m_object));
         }
 
+        set_parents();
         assert_invariant();
     }
 
@@ -14098,10 +19658,10 @@ class basic_json
     // other constructors and destructor //
     ///////////////////////////////////////
 
-    /// @private
-    basic_json(const detail::json_ref<basic_json>& ref)
-        : basic_json(ref.moved_or_copied())
-    {}
+    template<typename JsonRef,
+             detail::enable_if_t<detail::conjunction<detail::is_json_ref<JsonRef>,
+                                 std::is_same<typename JsonRef::value_type, basic_json>>::value, int> = 0 >
+    basic_json(const JsonRef& ref) : basic_json(ref.moved_or_copied()) {}
 
     /*!
     @brief copy constructor
@@ -14178,10 +19738,19 @@ class basic_json
                 break;
             }
 
+            case value_t::binary:
+            {
+                m_value = *other.m_value.binary;
+                break;
+            }
+
+            case value_t::null:
+            case value_t::discarded:
             default:
                 break;
         }
 
+        set_parents();
         assert_invariant();
     }
 
@@ -14216,12 +19785,13 @@ class basic_json
           m_value(std::move(other.m_value))
     {
         // check that passed value is valid
-        other.assert_invariant();
+        other.assert_invariant(false);
 
         // invalidate payload
         other.m_type = value_t::null;
         other.m_value = {};
 
+        set_parents();
         assert_invariant();
     }
 
@@ -14249,9 +19819,9 @@ class basic_json
     @since version 1.0.0
     */
     basic_json& operator=(basic_json other) noexcept (
-        std::is_nothrow_move_constructible<value_t>::value and
-        std::is_nothrow_move_assignable<value_t>::value and
-        std::is_nothrow_move_constructible<json_value>::value and
+        std::is_nothrow_move_constructible<value_t>::value&&
+        std::is_nothrow_move_assignable<value_t>::value&&
+        std::is_nothrow_move_constructible<json_value>::value&&
         std::is_nothrow_move_assignable<json_value>::value
     )
     {
@@ -14262,6 +19832,7 @@ class basic_json
         swap(m_type, other.m_type);
         swap(m_value, other.m_value);
 
+        set_parents();
         assert_invariant();
         return *this;
     }
@@ -14283,7 +19854,7 @@ class basic_json
     */
     ~basic_json() noexcept
     {
-        assert_invariant();
+        assert_invariant(false);
         m_value.destroy(m_type);
     }
 
@@ -14317,12 +19888,17 @@ class basic_json
     @param[in] error_handler  how to react on decoding errors; there are three
     possible values: `strict` (throws and exception in case a decoding error
     occurs; default), `replace` (replace invalid UTF-8 sequences with U+FFFD),
-    and `ignore` (ignore invalid UTF-8 sequences during serialization).
+    and `ignore` (ignore invalid UTF-8 sequences during serialization; all
+    bytes are copied to the output unchanged).
 
     @return string containing the serialization of the JSON value
 
     @throw type_error.316 if a string stored inside the JSON value is not
-                          UTF-8 encoded
+                          UTF-8 encoded and @a error_handler is set to strict
+
+    @note Binary values are serialized as object containing two keys:
+      - "bytes": an array of bytes as integers
+      - "subtype": the subtype as integer or "null" if the binary has no subtype
 
     @complexity Linear.
 
@@ -14337,7 +19913,8 @@ class basic_json
 
     @since version 1.0.0; indentation character @a indent_char, option
            @a ensure_ascii and exceptions added in version 3.0.0; error
-           handlers added in version 3.4.0.
+           handlers added in version 3.4.0; serialization of binary values added
+           in version 3.8.0.
     */
     string_t dump(const int indent = -1,
                   const char indent_char = ' ',
@@ -14376,6 +19953,7 @@ class basic_json
             number (floating-point)   | value_t::number_float
             object                    | value_t::object
             array                     | value_t::array
+            binary                    | value_t::binary
             discarded                 | value_t::discarded
 
     @complexity Constant.
@@ -14386,8 +19964,8 @@ class basic_json
     @liveexample{The following code exemplifies `type()` for all JSON
     types.,type}
 
-    @sa @ref operator value_t() -- return the type of the JSON value (implicit)
-    @sa @ref type_name() -- return the type as string
+    @sa see @ref operator value_t() -- return the type of the JSON value (implicit)
+    @sa see @ref type_name() -- return the type as string
 
     @since version 1.0.0
     */
@@ -14413,17 +19991,18 @@ class basic_json
     @liveexample{The following code exemplifies `is_primitive()` for all JSON
     types.,is_primitive}
 
-    @sa @ref is_structured() -- returns whether JSON value is structured
-    @sa @ref is_null() -- returns whether JSON value is `null`
-    @sa @ref is_string() -- returns whether JSON value is a string
-    @sa @ref is_boolean() -- returns whether JSON value is a boolean
-    @sa @ref is_number() -- returns whether JSON value is a number
+    @sa see @ref is_structured() -- returns whether JSON value is structured
+    @sa see @ref is_null() -- returns whether JSON value is `null`
+    @sa see @ref is_string() -- returns whether JSON value is a string
+    @sa see @ref is_boolean() -- returns whether JSON value is a boolean
+    @sa see @ref is_number() -- returns whether JSON value is a number
+    @sa see @ref is_binary() -- returns whether JSON value is a binary array
 
     @since version 1.0.0
     */
     constexpr bool is_primitive() const noexcept
     {
-        return is_null() or is_string() or is_boolean() or is_number();
+        return is_null() || is_string() || is_boolean() || is_number() || is_binary();
     }
 
     /*!
@@ -14442,15 +20021,15 @@ class basic_json
     @liveexample{The following code exemplifies `is_structured()` for all JSON
     types.,is_structured}
 
-    @sa @ref is_primitive() -- returns whether value is primitive
-    @sa @ref is_array() -- returns whether value is an array
-    @sa @ref is_object() -- returns whether value is an object
+    @sa see @ref is_primitive() -- returns whether value is primitive
+    @sa see @ref is_array() -- returns whether value is an array
+    @sa see @ref is_object() -- returns whether value is an object
 
     @since version 1.0.0
     */
     constexpr bool is_structured() const noexcept
     {
-        return is_array() or is_object();
+        return is_array() || is_object();
     }
 
     /*!
@@ -14472,7 +20051,7 @@ class basic_json
     */
     constexpr bool is_null() const noexcept
     {
-        return (m_type == value_t::null);
+        return m_type == value_t::null;
     }
 
     /*!
@@ -14494,7 +20073,7 @@ class basic_json
     */
     constexpr bool is_boolean() const noexcept
     {
-        return (m_type == value_t::boolean);
+        return m_type == value_t::boolean;
     }
 
     /*!
@@ -14514,17 +20093,17 @@ class basic_json
     @liveexample{The following code exemplifies `is_number()` for all JSON
     types.,is_number}
 
-    @sa @ref is_number_integer() -- check if value is an integer or unsigned
+    @sa see @ref is_number_integer() -- check if value is an integer or unsigned
     integer number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    @sa see @ref is_number_unsigned() -- check if value is an unsigned integer
     number
-    @sa @ref is_number_float() -- check if value is a floating-point number
+    @sa see @ref is_number_float() -- check if value is a floating-point number
 
     @since version 1.0.0
     */
     constexpr bool is_number() const noexcept
     {
-        return is_number_integer() or is_number_float();
+        return is_number_integer() || is_number_float();
     }
 
     /*!
@@ -14544,16 +20123,16 @@ class basic_json
     @liveexample{The following code exemplifies `is_number_integer()` for all
     JSON types.,is_number_integer}
 
-    @sa @ref is_number() -- check if value is a number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    @sa see @ref is_number() -- check if value is a number
+    @sa see @ref is_number_unsigned() -- check if value is an unsigned integer
     number
-    @sa @ref is_number_float() -- check if value is a floating-point number
+    @sa see @ref is_number_float() -- check if value is a floating-point number
 
     @since version 1.0.0
     */
     constexpr bool is_number_integer() const noexcept
     {
-        return (m_type == value_t::number_integer or m_type == value_t::number_unsigned);
+        return m_type == value_t::number_integer || m_type == value_t::number_unsigned;
     }
 
     /*!
@@ -14572,16 +20151,16 @@ class basic_json
     @liveexample{The following code exemplifies `is_number_unsigned()` for all
     JSON types.,is_number_unsigned}
 
-    @sa @ref is_number() -- check if value is a number
-    @sa @ref is_number_integer() -- check if value is an integer or unsigned
+    @sa see @ref is_number() -- check if value is a number
+    @sa see @ref is_number_integer() -- check if value is an integer or unsigned
     integer number
-    @sa @ref is_number_float() -- check if value is a floating-point number
+    @sa see @ref is_number_float() -- check if value is a floating-point number
 
     @since version 2.0.0
     */
     constexpr bool is_number_unsigned() const noexcept
     {
-        return (m_type == value_t::number_unsigned);
+        return m_type == value_t::number_unsigned;
     }
 
     /*!
@@ -14600,16 +20179,16 @@ class basic_json
     @liveexample{The following code exemplifies `is_number_float()` for all
     JSON types.,is_number_float}
 
-    @sa @ref is_number() -- check if value is number
-    @sa @ref is_number_integer() -- check if value is an integer number
-    @sa @ref is_number_unsigned() -- check if value is an unsigned integer
+    @sa see @ref is_number() -- check if value is number
+    @sa see @ref is_number_integer() -- check if value is an integer number
+    @sa see @ref is_number_unsigned() -- check if value is an unsigned integer
     number
 
     @since version 1.0.0
     */
     constexpr bool is_number_float() const noexcept
     {
-        return (m_type == value_t::number_float);
+        return m_type == value_t::number_float;
     }
 
     /*!
@@ -14631,7 +20210,7 @@ class basic_json
     */
     constexpr bool is_object() const noexcept
     {
-        return (m_type == value_t::object);
+        return m_type == value_t::object;
     }
 
     /*!
@@ -14653,7 +20232,7 @@ class basic_json
     */
     constexpr bool is_array() const noexcept
     {
-        return (m_type == value_t::array);
+        return m_type == value_t::array;
     }
 
     /*!
@@ -14675,7 +20254,29 @@ class basic_json
     */
     constexpr bool is_string() const noexcept
     {
-        return (m_type == value_t::string);
+        return m_type == value_t::string;
+    }
+
+    /*!
+    @brief return whether value is a binary array
+
+    This function returns true if and only if the JSON value is a binary array.
+
+    @return `true` if type is binary array, `false` otherwise.
+
+    @complexity Constant.
+
+    @exceptionsafety No-throw guarantee: this member function never throws
+    exceptions.
+
+    @liveexample{The following code exemplifies `is_binary()` for all JSON
+    types.,is_binary}
+
+    @since version 3.8.0
+    */
+    constexpr bool is_binary() const noexcept
+    {
+        return m_type == value_t::binary;
     }
 
     /*!
@@ -14702,7 +20303,7 @@ class basic_json
     */
     constexpr bool is_discarded() const noexcept
     {
-        return (m_type == value_t::discarded);
+        return m_type == value_t::discarded;
     }
 
     /*!
@@ -14721,8 +20322,8 @@ class basic_json
     @liveexample{The following code exemplifies the @ref value_t operator for
     all JSON types.,operator__value_t}
 
-    @sa @ref type() -- return the type of the JSON value (explicit)
-    @sa @ref type_name() -- return the type as string
+    @sa see @ref type() -- return the type of the JSON value (explicit)
+    @sa see @ref type_name() -- return the type as string
 
     @since version 1.0.0
     */
@@ -14741,12 +20342,12 @@ class basic_json
     /// get a boolean (explicit)
     boolean_t get_impl(boolean_t* /*unused*/) const
     {
-        if (JSON_LIKELY(is_boolean()))
+        if (JSON_HEDLEY_LIKELY(is_boolean()))
         {
             return m_value.boolean;
         }
 
-        JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(type_name())));
+        JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(type_name()), *this));
     }
 
     /// get a pointer to the value (object)
@@ -14833,6 +20434,18 @@ class basic_json
         return is_number_float() ? &m_value.number_float : nullptr;
     }
 
+    /// get a pointer to the value (binary)
+    binary_t* get_impl_ptr(binary_t* /*unused*/) noexcept
+    {
+        return is_binary() ? m_value.binary : nullptr;
+    }
+
+    /// get a pointer to the value (binary)
+    constexpr const binary_t* get_impl_ptr(const binary_t* /*unused*/) const noexcept
+    {
+        return is_binary() ? m_value.binary : nullptr;
+    }
+
     /*!
     @brief helper function to implement get_ref()
 
@@ -14848,14 +20461,14 @@ class basic_json
     static ReferenceType get_ref_impl(ThisType& obj)
     {
         // delegate the call to get_ptr<>()
-        auto ptr = obj.template get_ptr<typename std::add_pointer<ReferenceType>::type>();
+        auto* ptr = obj.template get_ptr<typename std::add_pointer<ReferenceType>::type>();
 
-        if (JSON_LIKELY(ptr != nullptr))
+        if (JSON_HEDLEY_LIKELY(ptr != nullptr))
         {
             return *ptr;
         }
 
-        JSON_THROW(type_error::create(303, "incompatible ReferenceType for get_ref, actual type is " + std::string(obj.type_name())));
+        JSON_THROW(type_error::create(303, "incompatible ReferenceType for get_ref, actual type is " + std::string(obj.type_name()), obj));
     }
 
   public:
@@ -14864,50 +20477,53 @@ class basic_json
     /// @{
 
     /*!
-    @brief get special-case overload
+    @brief get a pointer value (implicit)
 
-    This overloads avoids a lot of template boilerplate, it can be seen as the
-    identity method
+    Implicit pointer access to the internally stored JSON value. No copies are
+    made.
 
-    @tparam BasicJsonType == @ref basic_json
+    @warning Writing data to the pointee of the result yields an undefined
+    state.
 
-    @return a copy of *this
+    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
+    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
+    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
+    assertion.
+
+    @return pointer to the internally stored JSON value if the requested
+    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
 
     @complexity Constant.
 
-    @since version 2.1.0
+    @liveexample{The example below shows how pointers to internal values of a
+    JSON value can be requested. Note that no type conversions are made and a
+    `nullptr` is returned if the value and the requested pointer type does not
+    match.,get_ptr}
+
+    @since version 1.0.0
     */
-    template<typename BasicJsonType, detail::enable_if_t<
-                 std::is_same<typename std::remove_const<BasicJsonType>::type, basic_json_t>::value,
-                 int> = 0>
-    basic_json get() const
+    template<typename PointerType, typename std::enable_if<
+                 std::is_pointer<PointerType>::value, int>::type = 0>
+    auto get_ptr() noexcept -> decltype(std::declval<basic_json_t&>().get_impl_ptr(std::declval<PointerType>()))
     {
-        return *this;
+        // delegate the call to get_impl_ptr<>()
+        return get_impl_ptr(static_cast<PointerType>(nullptr));
     }
 
     /*!
-    @brief get special-case overload
-
-    This overloads converts the current @ref basic_json in a different
-    @ref basic_json type
-
-    @tparam BasicJsonType == @ref basic_json
-
-    @return a copy of *this, converted into @tparam BasicJsonType
-
-    @complexity Depending on the implementation of the called `from_json()`
-                method.
-
-    @since version 3.2.0
+    @brief get a pointer value (implicit)
+    @copydoc get_ptr()
     */
-    template<typename BasicJsonType, detail::enable_if_t<
-                 not std::is_same<BasicJsonType, basic_json>::value and
-                 detail::is_basic_json<BasicJsonType>::value, int> = 0>
-    BasicJsonType get() const
+    template < typename PointerType, typename std::enable_if <
+                   std::is_pointer<PointerType>::value&&
+                   std::is_const<typename std::remove_pointer<PointerType>::type>::value, int >::type = 0 >
+    constexpr auto get_ptr() const noexcept -> decltype(std::declval<const basic_json_t&>().get_impl_ptr(std::declval<PointerType>()))
     {
-        return *this;
+        // delegate the call to get_impl_ptr<>() const
+        return get_impl_ptr(static_cast<PointerType>(nullptr));
     }
 
+  private:
     /*!
     @brief get a value (explicit)
 
@@ -14931,7 +20547,6 @@ class basic_json
     - @ref json_serializer<ValueType> does not have a `from_json()` method of
       the form `ValueType from_json(const basic_json&)`
 
-    @tparam ValueTypeCV the provided value type
     @tparam ValueType the returned value type
 
     @return copy of the JSON value, converted to @a ValueType
@@ -14947,24 +20562,15 @@ class basic_json
 
     @since version 2.1.0
     */
-    template<typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>,
-             detail::enable_if_t <
-                 not detail::is_basic_json<ValueType>::value and
-                 detail::has_from_json<basic_json_t, ValueType>::value and
-                 not detail::has_non_default_from_json<basic_json_t, ValueType>::value,
-                 int> = 0>
-    ValueType get() const noexcept(noexcept(
-                                       JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), std::declval<ValueType&>())))
+    template < typename ValueType,
+               detail::enable_if_t <
+                   detail::is_default_constructible<ValueType>::value&&
+                   detail::has_from_json<basic_json_t, ValueType>::value,
+                   int > = 0 >
+    ValueType get_impl(detail::priority_tag<0> /*unused*/) const noexcept(noexcept(
+                JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), std::declval<ValueType&>())))
     {
-        // we cannot static_assert on ValueTypeCV being non-const, because
-        // there is support for get<const basic_json_t>(), which is why we
-        // still need the uncvref
-        static_assert(not std::is_reference<ValueTypeCV>::value,
-                      "get() cannot be used with reference types, you might want to use get_ref()");
-        static_assert(std::is_default_constructible<ValueType>::value,
-                      "types must be DefaultConstructible when used with get()");
-
-        ValueType ret;
+        auto ret = ValueType();
         JSONSerializer<ValueType>::from_json(*this, ret);
         return ret;
     }
@@ -14980,7 +20586,7 @@ class basic_json
 
     The function is equivalent to executing
     @code {.cpp}
-    return JSONSerializer<ValueTypeCV>::from_json(*this);
+    return JSONSerializer<ValueType>::from_json(*this);
     @endcode
 
     This overloads is chosen if:
@@ -14991,7 +20597,6 @@ class basic_json
     @note If @ref json_serializer<ValueType> has both overloads of
     `from_json()`, this one is chosen.
 
-    @tparam ValueTypeCV the provided value type
     @tparam ValueType the returned value type
 
     @return copy of the JSON value, converted to @a ValueType
@@ -15000,109 +20605,116 @@ class basic_json
 
     @since version 2.1.0
     */
-    template<typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>,
-             detail::enable_if_t<not std::is_same<basic_json_t, ValueType>::value and
-                                 detail::has_non_default_from_json<basic_json_t, ValueType>::value,
-                                 int> = 0>
-    ValueType get() const noexcept(noexcept(
-                                       JSONSerializer<ValueTypeCV>::from_json(std::declval<const basic_json_t&>())))
+    template < typename ValueType,
+               detail::enable_if_t <
+                   detail::has_non_default_from_json<basic_json_t, ValueType>::value,
+                   int > = 0 >
+    ValueType get_impl(detail::priority_tag<1> /*unused*/) const noexcept(noexcept(
+                JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>())))
     {
-        static_assert(not std::is_reference<ValueTypeCV>::value,
-                      "get() cannot be used with reference types, you might want to use get_ref()");
-        return JSONSerializer<ValueTypeCV>::from_json(*this);
+        return JSONSerializer<ValueType>::from_json(*this);
     }
 
     /*!
-    @brief get a value (explicit)
+    @brief get special-case overload
 
-    Explicit type conversion between the JSON value and a compatible value.
-    The value is filled into the input parameter by calling the @ref json_serializer<ValueType>
-    `from_json()` method.
+    This overloads converts the current @ref basic_json in a different
+    @ref basic_json type
 
-    The function is equivalent to executing
-    @code {.cpp}
-    ValueType v;
-    JSONSerializer<ValueType>::from_json(*this, v);
-    @endcode
+    @tparam BasicJsonType == @ref basic_json
 
-    This overloads is chosen if:
-    - @a ValueType is not @ref basic_json,
-    - @ref json_serializer<ValueType> has a `from_json()` method of the form
-      `void from_json(const basic_json&, ValueType&)`, and
+    @return a copy of *this, converted into @a BasicJsonType
 
-    @tparam ValueType the input parameter type.
+    @complexity Depending on the implementation of the called `from_json()`
+                method.
 
-    @return the input parameter, allowing chaining calls.
+    @since version 3.2.0
+    */
+    template < typename BasicJsonType,
+               detail::enable_if_t <
+                   detail::is_basic_json<BasicJsonType>::value,
+                   int > = 0 >
+    BasicJsonType get_impl(detail::priority_tag<2> /*unused*/) const
+    {
+        return *this;
+    }
 
-    @throw what @ref json_serializer<ValueType> `from_json()` method throws
+    /*!
+    @brief get special-case overload
 
-    @liveexample{The example below shows several conversions from JSON values
-    to other types. There a few things to note: (1) Floating-point numbers can
-    be converted to integers\, (2) A JSON array can be converted to a standard
-    `std::vector<short>`\, (3) A JSON object can be converted to C++
-    associative containers such as `std::unordered_map<std::string\,
-    json>`.,get_to}
+    This overloads avoids a lot of template boilerplate, it can be seen as the
+    identity method
 
-    @since version 3.3.0
+    @tparam BasicJsonType == @ref basic_json
+
+    @return a copy of *this
+
+    @complexity Constant.
+
+    @since version 2.1.0
     */
-    template<typename ValueType,
-             detail::enable_if_t <
-                 not detail::is_basic_json<ValueType>::value and
-                 detail::has_from_json<basic_json_t, ValueType>::value,
+    template<typename BasicJsonType,
+             detail::enable_if_t<
+                 std::is_same<BasicJsonType, basic_json_t>::value,
                  int> = 0>
-    ValueType & get_to(ValueType& v) const noexcept(noexcept(
-                JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), v)))
+    basic_json get_impl(detail::priority_tag<3> /*unused*/) const
     {
-        JSONSerializer<ValueType>::from_json(*this, v);
-        return v;
+        return *this;
     }
 
+    /*!
+    @brief get a pointer value (explicit)
+    @copydoc get()
+    */
+    template<typename PointerType,
+             detail::enable_if_t<
+                 std::is_pointer<PointerType>::value,
+                 int> = 0>
+    constexpr auto get_impl(detail::priority_tag<4> /*unused*/) const noexcept
+    -> decltype(std::declval<const basic_json_t&>().template get_ptr<PointerType>())
+    {
+        // delegate the call to get_ptr
+        return get_ptr<PointerType>();
+    }
 
+  public:
     /*!
-    @brief get a pointer value (implicit)
+    @brief get a (pointer) value (explicit)
 
-    Implicit pointer access to the internally stored JSON value. No copies are
-    made.
+    Performs explicit type conversion between the JSON value and a compatible value if required.
 
-    @warning Writing data to the pointee of the result yields an undefined
-    state.
+    - If the requested type is a pointer to the internally stored JSON value that pointer is returned.
+    No copies are made.
 
-    @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref
-    object_t, @ref string_t, @ref boolean_t, @ref number_integer_t,
-    @ref number_unsigned_t, or @ref number_float_t. Enforced by a static
-    assertion.
+    - If the requested type is the current @ref basic_json, or a different @ref basic_json convertible
+    from the current @ref basic_json.
 
-    @return pointer to the internally stored JSON value if the requested
-    pointer type @a PointerType fits to the JSON value; `nullptr` otherwise
+    - Otherwise the value is converted by calling the @ref json_serializer<ValueType> `from_json()`
+    method.
 
-    @complexity Constant.
+    @tparam ValueTypeCV the provided value type
+    @tparam ValueType the returned value type
 
-    @liveexample{The example below shows how pointers to internal values of a
-    JSON value can be requested. Note that no type conversions are made and a
-    `nullptr` is returned if the value and the requested pointer type does not
-    match.,get_ptr}
+    @return copy of the JSON value, converted to @tparam ValueType if necessary
 
-    @since version 1.0.0
-    */
-    template<typename PointerType, typename std::enable_if<
-                 std::is_pointer<PointerType>::value, int>::type = 0>
-    auto get_ptr() noexcept -> decltype(std::declval<basic_json_t&>().get_impl_ptr(std::declval<PointerType>()))
-    {
-        // delegate the call to get_impl_ptr<>()
-        return get_impl_ptr(static_cast<PointerType>(nullptr));
-    }
+    @throw what @ref json_serializer<ValueType> `from_json()` method throws if conversion is required
 
-    /*!
-    @brief get a pointer value (implicit)
-    @copydoc get_ptr()
+    @since version 2.1.0
     */
-    template<typename PointerType, typename std::enable_if<
-                 std::is_pointer<PointerType>::value and
-                 std::is_const<typename std::remove_pointer<PointerType>::type>::value, int>::type = 0>
-    constexpr auto get_ptr() const noexcept -> decltype(std::declval<const basic_json_t&>().get_impl_ptr(std::declval<PointerType>()))
+    template < typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>>
+#if defined(JSON_HAS_CPP_14)
+    constexpr
+#endif
+    auto get() const noexcept(
+    noexcept(std::declval<const basic_json_t&>().template get_impl<ValueType>(detail::priority_tag<4> {})))
+    -> decltype(std::declval<const basic_json_t&>().template get_impl<ValueType>(detail::priority_tag<4> {}))
     {
-        // delegate the call to get_impl_ptr<>() const
-        return get_impl_ptr(static_cast<PointerType>(nullptr));
+        // we cannot static_assert on ValueTypeCV being non-const, because
+        // there is support for get<const basic_json_t>(), which is why we
+        // still need the uncvref
+        static_assert(!std::is_reference<ValueTypeCV>::value,
+                      "get() cannot be used with reference types, you might want to use get_ref()");
+        return get_impl<ValueType>(detail::priority_tag<4> {});
     }
 
     /*!
@@ -15128,7 +20740,7 @@ class basic_json
     `nullptr` is returned if the value and the requested pointer type does not
     match.,get__PointerType}
 
-    @sa @ref get_ptr() for explicit pointer-member access
+    @sa see @ref get_ptr() for explicit pointer-member access
 
     @since version 1.0.0
     */
@@ -15140,16 +20752,74 @@ class basic_json
         return get_ptr<PointerType>();
     }
 
-    /*!
-    @brief get a pointer value (explicit)
-    @copydoc get()
-    */
-    template<typename PointerType, typename std::enable_if<
-                 std::is_pointer<PointerType>::value, int>::type = 0>
-    constexpr auto get() const noexcept -> decltype(std::declval<const basic_json_t&>().template get_ptr<PointerType>())
-    {
-        // delegate the call to get_ptr
-        return get_ptr<PointerType>();
+    /*!
+    @brief get a value (explicit)
+
+    Explicit type conversion between the JSON value and a compatible value.
+    The value is filled into the input parameter by calling the @ref json_serializer<ValueType>
+    `from_json()` method.
+
+    The function is equivalent to executing
+    @code {.cpp}
+    ValueType v;
+    JSONSerializer<ValueType>::from_json(*this, v);
+    @endcode
+
+    This overloads is chosen if:
+    - @a ValueType is not @ref basic_json,
+    - @ref json_serializer<ValueType> has a `from_json()` method of the form
+      `void from_json(const basic_json&, ValueType&)`, and
+
+    @tparam ValueType the input parameter type.
+
+    @return the input parameter, allowing chaining calls.
+
+    @throw what @ref json_serializer<ValueType> `from_json()` method throws
+
+    @liveexample{The example below shows several conversions from JSON values
+    to other types. There a few things to note: (1) Floating-point numbers can
+    be converted to integers\, (2) A JSON array can be converted to a standard
+    `std::vector<short>`\, (3) A JSON object can be converted to C++
+    associative containers such as `std::unordered_map<std::string\,
+    json>`.,get_to}
+
+    @since version 3.3.0
+    */
+    template < typename ValueType,
+               detail::enable_if_t <
+                   !detail::is_basic_json<ValueType>::value&&
+                   detail::has_from_json<basic_json_t, ValueType>::value,
+                   int > = 0 >
+    ValueType & get_to(ValueType& v) const noexcept(noexcept(
+                JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), v)))
+    {
+        JSONSerializer<ValueType>::from_json(*this, v);
+        return v;
+    }
+
+    // specialization to allow to call get_to with a basic_json value
+    // see https://github.com/nlohmann/json/issues/2175
+    template<typename ValueType,
+             detail::enable_if_t <
+                 detail::is_basic_json<ValueType>::value,
+                 int> = 0>
+    ValueType & get_to(ValueType& v) const
+    {
+        v = *this;
+        return v;
+    }
+
+    template <
+        typename T, std::size_t N,
+        typename Array = T (&)[N], // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+        detail::enable_if_t <
+            detail::has_from_json<basic_json_t, Array>::value, int > = 0 >
+    Array get_to(T (&v)[N]) const // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+    noexcept(noexcept(JSONSerializer<Array>::from_json(
+                          std::declval<const basic_json_t&>(), v)))
+    {
+        JSONSerializer<Array>::from_json(*this, v);
+        return v;
     }
 
     /*!
@@ -15190,9 +20860,9 @@ class basic_json
     @brief get a reference value (implicit)
     @copydoc get_ref()
     */
-    template<typename ReferenceType, typename std::enable_if<
-                 std::is_reference<ReferenceType>::value and
-                 std::is_const<typename std::remove_reference<ReferenceType>::type>::value, int>::type = 0>
+    template < typename ReferenceType, typename std::enable_if <
+                   std::is_reference<ReferenceType>::value&&
+                   std::is_const<typename std::remove_reference<ReferenceType>::type>::value, int >::type = 0 >
     ReferenceType get_ref() const
     {
         // delegate call to get_ref_impl
@@ -15229,25 +20899,54 @@ class basic_json
     @since version 1.0.0
     */
     template < typename ValueType, typename std::enable_if <
-                   not std::is_pointer<ValueType>::value and
-                   not std::is_same<ValueType, detail::json_ref<basic_json>>::value and
-                   not std::is_same<ValueType, typename string_t::value_type>::value and
-                   not detail::is_basic_json<ValueType>::value
-
-#ifndef _MSC_VER  // fix for issue #167 operator<< ambiguity under VS2015
-                   and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value
-#if defined(JSON_HAS_CPP_17) && defined(_MSC_VER) and _MSC_VER <= 1914
-                   and not std::is_same<ValueType, typename std::string_view>::value
+                   detail::conjunction <
+                       detail::negation<std::is_pointer<ValueType>>,
+                       detail::negation<std::is_same<ValueType, detail::json_ref<basic_json>>>,
+                                        detail::negation<std::is_same<ValueType, typename string_t::value_type>>,
+                                        detail::negation<detail::is_basic_json<ValueType>>,
+                                        detail::negation<std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>>,
+
+#if defined(JSON_HAS_CPP_17) && (defined(__GNUC__) || (defined(_MSC_VER) && _MSC_VER >= 1910 && _MSC_VER <= 1914))
+                                                detail::negation<std::is_same<ValueType, std::string_view>>,
 #endif
-#endif
-                   and detail::is_detected<detail::get_template_function, const basic_json_t&, ValueType>::value
-                   , int >::type = 0 >
-    operator ValueType() const
+                                                detail::is_detected_lazy<detail::get_template_function, const basic_json_t&, ValueType>
+                                                >::value, int >::type = 0 >
+                                        JSON_EXPLICIT operator ValueType() const
     {
         // delegate the call to get<>() const
         return get<ValueType>();
     }
 
+    /*!
+    @return reference to the binary value
+
+    @throw type_error.302 if the value is not binary
+
+    @sa see @ref is_binary() to check if the value is binary
+
+    @since version 3.8.0
+    */
+    binary_t& get_binary()
+    {
+        if (!is_binary())
+        {
+            JSON_THROW(type_error::create(302, "type must be binary, but is " + std::string(type_name()), *this));
+        }
+
+        return *get_ptr<binary_t*>();
+    }
+
+    /// @copydoc get_binary()
+    const binary_t& get_binary() const
+    {
+        if (!is_binary())
+        {
+            JSON_THROW(type_error::create(302, "type must be binary, but is " + std::string(type_name()), *this));
+        }
+
+        return *get_ptr<const binary_t*>();
+    }
+
     /// @}
 
 
@@ -15288,21 +20987,21 @@ class basic_json
     reference at(size_type idx)
     {
         // at only works for arrays
-        if (JSON_LIKELY(is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
         {
             JSON_TRY
             {
-                return m_value.array->at(idx);
+                return set_parent(m_value.array->at(idx));
             }
             JSON_CATCH (std::out_of_range&)
             {
                 // create better exception explanation
-                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range", *this));
             }
         }
         else
         {
-            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name()), *this));
         }
     }
 
@@ -15335,7 +21034,7 @@ class basic_json
     const_reference at(size_type idx) const
     {
         // at only works for arrays
-        if (JSON_LIKELY(is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
         {
             JSON_TRY
             {
@@ -15344,12 +21043,12 @@ class basic_json
             JSON_CATCH (std::out_of_range&)
             {
                 // create better exception explanation
-                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range", *this));
             }
         }
         else
         {
-            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name()), *this));
         }
     }
 
@@ -15373,9 +21072,9 @@ class basic_json
 
     @complexity Logarithmic in the size of the container.
 
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    @sa see @ref operator[](const typename object_t::key_type&) for unchecked
     access by reference
-    @sa @ref value() for access by value with a default value
+    @sa see @ref value() for access by value with a default value
 
     @since version 1.0.0
 
@@ -15386,21 +21085,21 @@ class basic_json
     reference at(const typename object_t::key_type& key)
     {
         // at only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
             JSON_TRY
             {
-                return m_value.object->at(key);
+                return set_parent(m_value.object->at(key));
             }
             JSON_CATCH (std::out_of_range&)
             {
                 // create better exception explanation
-                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
+                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found", *this));
             }
         }
         else
         {
-            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name()), *this));
         }
     }
 
@@ -15424,9 +21123,9 @@ class basic_json
 
     @complexity Logarithmic in the size of the container.
 
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    @sa see @ref operator[](const typename object_t::key_type&) for unchecked
     access by reference
-    @sa @ref value() for access by value with a default value
+    @sa see @ref value() for access by value with a default value
 
     @since version 1.0.0
 
@@ -15437,7 +21136,7 @@ class basic_json
     const_reference at(const typename object_t::key_type& key) const
     {
         // at only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
             JSON_TRY
             {
@@ -15446,12 +21145,12 @@ class basic_json
             JSON_CATCH (std::out_of_range&)
             {
                 // create better exception explanation
-                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found"));
+                JSON_THROW(out_of_range::create(403, "key '" + key + "' not found", *this));
             }
         }
         else
         {
-            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(304, "cannot use at() with " + std::string(type_name()), *this));
         }
     }
 
@@ -15491,20 +21190,37 @@ class basic_json
         }
 
         // operator[] only works for arrays
-        if (JSON_LIKELY(is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
         {
             // fill up array with null values if given idx is outside range
             if (idx >= m_value.array->size())
             {
-                m_value.array->insert(m_value.array->end(),
-                                      idx - m_value.array->size() + 1,
-                                      basic_json());
+#if JSON_DIAGNOSTICS
+                // remember array size & capacity before resizing
+                const auto old_size = m_value.array->size();
+                const auto old_capacity = m_value.array->capacity();
+#endif
+                m_value.array->resize(idx + 1);
+
+#if JSON_DIAGNOSTICS
+                if (JSON_HEDLEY_UNLIKELY(m_value.array->capacity() != old_capacity))
+                {
+                    // capacity has changed: update all parents
+                    set_parents();
+                }
+                else
+                {
+                    // set parent for values added above
+                    set_parents(begin() + static_cast<typename iterator::difference_type>(old_size), static_cast<typename iterator::difference_type>(idx + 1 - old_size));
+                }
+#endif
+                assert_invariant();
             }
 
             return m_value.array->operator[](idx);
         }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with a numeric argument with " + std::string(type_name())));
+        JSON_THROW(type_error::create(305, "cannot use operator[] with a numeric argument with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -15529,12 +21245,12 @@ class basic_json
     const_reference operator[](size_type idx) const
     {
         // const operator[] only works for arrays
-        if (JSON_LIKELY(is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
         {
             return m_value.array->operator[](idx);
         }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with a numeric argument with " + std::string(type_name())));
+        JSON_THROW(type_error::create(305, "cannot use operator[] with a numeric argument with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -15558,9 +21274,9 @@ class basic_json
     @liveexample{The example below shows how object elements can be read and
     written using the `[]` operator.,operatorarray__key_type}
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
+    @sa see @ref at(const typename object_t::key_type&) for access by reference
     with range checking
-    @sa @ref value() for access by value with a default value
+    @sa see @ref value() for access by value with a default value
 
     @since version 1.0.0
     */
@@ -15575,12 +21291,12 @@ class basic_json
         }
 
         // operator[] only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
-            return m_value.object->operator[](key);
+            return set_parent(m_value.object->operator[](key));
         }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with a string argument with " + std::string(type_name())));
+        JSON_THROW(type_error::create(305, "cannot use operator[] with a string argument with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -15607,22 +21323,22 @@ class basic_json
     @liveexample{The example below shows how object elements can be read using
     the `[]` operator.,operatorarray__key_type_const}
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
+    @sa see @ref at(const typename object_t::key_type&) for access by reference
     with range checking
-    @sa @ref value() for access by value with a default value
+    @sa see @ref value() for access by value with a default value
 
     @since version 1.0.0
     */
     const_reference operator[](const typename object_t::key_type& key) const
     {
         // const operator[] only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
-            assert(m_value.object->find(key) != m_value.object->end());
+            JSON_ASSERT(m_value.object->find(key) != m_value.object->end());
             return m_value.object->find(key)->second;
         }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with a string argument with " + std::string(type_name())));
+        JSON_THROW(type_error::create(305, "cannot use operator[] with a string argument with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -15646,13 +21362,14 @@ class basic_json
     @liveexample{The example below shows how object elements can be read and
     written using the `[]` operator.,operatorarray__key_type}
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
+    @sa see @ref at(const typename object_t::key_type&) for access by reference
     with range checking
-    @sa @ref value() for access by value with a default value
+    @sa see @ref value() for access by value with a default value
 
     @since version 1.1.0
     */
     template<typename T>
+    JSON_HEDLEY_NON_NULL(2)
     reference operator[](T* key)
     {
         // implicitly convert null to object
@@ -15664,12 +21381,12 @@ class basic_json
         }
 
         // at only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
-            return m_value.object->operator[](key);
+            return set_parent(m_value.object->operator[](key));
         }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with a string argument with " + std::string(type_name())));
+        JSON_THROW(type_error::create(305, "cannot use operator[] with a string argument with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -15696,23 +21413,24 @@ class basic_json
     @liveexample{The example below shows how object elements can be read using
     the `[]` operator.,operatorarray__key_type_const}
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
+    @sa see @ref at(const typename object_t::key_type&) for access by reference
     with range checking
-    @sa @ref value() for access by value with a default value
+    @sa see @ref value() for access by value with a default value
 
     @since version 1.1.0
     */
     template<typename T>
+    JSON_HEDLEY_NON_NULL(2)
     const_reference operator[](T* key) const
     {
         // at only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
-            assert(m_value.object->find(key) != m_value.object->end());
+            JSON_ASSERT(m_value.object->find(key) != m_value.object->end());
             return m_value.object->find(key)->second;
         }
 
-        JSON_THROW(type_error::create(305, "cannot use operator[] with a string argument with " + std::string(type_name())));
+        JSON_THROW(type_error::create(305, "cannot use operator[] with a string argument with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -15748,6 +21466,8 @@ class basic_json
     @return copy of the element at key @a key or @a default_value if @a key
     is not found
 
+    @throw type_error.302 if @a default_value does not match the type of the
+    value at @a key
     @throw type_error.306 if the JSON value is not an object; in that case,
     using `value()` with a key makes no sense.
 
@@ -15756,31 +21476,33 @@ class basic_json
     @liveexample{The example below shows how object elements can be queried
     with a default value.,basic_json__value}
 
-    @sa @ref at(const typename object_t::key_type&) for access by reference
+    @sa see @ref at(const typename object_t::key_type&) for access by reference
     with range checking
-    @sa @ref operator[](const typename object_t::key_type&) for unchecked
+    @sa see @ref operator[](const typename object_t::key_type&) for unchecked
     access by reference
 
     @since version 1.0.0
     */
-    template<class ValueType, typename std::enable_if<
-                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
+    // using std::is_convertible in a std::enable_if will fail when using explicit conversions
+    template < class ValueType, typename std::enable_if <
+                   detail::is_getable<basic_json_t, ValueType>::value
+                   && !std::is_same<value_t, ValueType>::value, int >::type = 0 >
     ValueType value(const typename object_t::key_type& key, const ValueType& default_value) const
     {
         // at only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
             // if key is found, return value and given default value otherwise
             const auto it = find(key);
             if (it != end())
             {
-                return *it;
+                return it->template get<ValueType>();
             }
 
             return default_value;
         }
 
-        JSON_THROW(type_error::create(306, "cannot use value() with " + std::string(type_name())));
+        JSON_THROW(type_error::create(306, "cannot use value() with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -15821,6 +21543,8 @@ class basic_json
     @return copy of the element at key @a key or @a default_value if @a key
     is not found
 
+    @throw type_error.302 if @a default_value does not match the type of the
+    value at @a ptr
     @throw type_error.306 if the JSON value is not an object; in that case,
     using `value()` with a key makes no sense.
 
@@ -15829,21 +21553,21 @@ class basic_json
     @liveexample{The example below shows how object elements can be queried
     with a default value.,basic_json__value_ptr}
 
-    @sa @ref operator[](const json_pointer&) for unchecked access by reference
+    @sa see @ref operator[](const json_pointer&) for unchecked access by reference
 
     @since version 2.0.2
     */
     template<class ValueType, typename std::enable_if<
-                 std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0>
+                 detail::is_getable<basic_json_t, ValueType>::value, int>::type = 0>
     ValueType value(const json_pointer& ptr, const ValueType& default_value) const
     {
         // at only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
             // if pointer resolves a value, return it or use default value
             JSON_TRY
             {
-                return ptr.get_checked(this);
+                return ptr.get_checked(this).template get<ValueType>();
             }
             JSON_INTERNAL_CATCH (out_of_range&)
             {
@@ -15851,13 +21575,14 @@ class basic_json
             }
         }
 
-        JSON_THROW(type_error::create(306, "cannot use value() with " + std::string(type_name())));
+        JSON_THROW(type_error::create(306, "cannot use value() with " + std::string(type_name()), *this));
     }
 
     /*!
     @brief overload for a default value of type const char*
     @copydoc basic_json::value(const json_pointer&, ValueType) const
     */
+    JSON_HEDLEY_NON_NULL(3)
     string_t value(const json_pointer& ptr, const char* default_value) const
     {
         return value(ptr, string_t(default_value));
@@ -15870,8 +21595,8 @@ class basic_json
     container `c`, the expression `c.front()` is equivalent to `*c.begin()`.
 
     @return In case of a structured type (array or object), a reference to the
-    first element is returned. In case of number, string, or boolean values, a
-    reference to the value is returned.
+    first element is returned. In case of number, string, boolean, or binary
+    values, a reference to the value is returned.
 
     @complexity Constant.
 
@@ -15884,7 +21609,7 @@ class basic_json
 
     @liveexample{The following code shows an example for `front()`.,front}
 
-    @sa @ref back() -- access the last element
+    @sa see @ref back() -- access the last element
 
     @since version 1.0.0
     */
@@ -15913,8 +21638,8 @@ class basic_json
     @endcode
 
     @return In case of a structured type (array or object), a reference to the
-    last element is returned. In case of number, string, or boolean values, a
-    reference to the value is returned.
+    last element is returned. In case of number, string, boolean, or binary
+    values, a reference to the value is returned.
 
     @complexity Constant.
 
@@ -15928,7 +21653,7 @@ class basic_json
 
     @liveexample{The following code shows an example for `back()`.,back}
 
-    @sa @ref front() -- access the first element
+    @sa see @ref front() -- access the first element
 
     @since version 1.0.0
     */
@@ -15980,31 +21705,31 @@ class basic_json
     @complexity The complexity depends on the type:
     - objects: amortized constant
     - arrays: linear in distance between @a pos and the end of the container
-    - strings: linear in the length of the string
+    - strings and binary: linear in the length of the member
     - other types: constant
 
     @liveexample{The example shows the result of `erase()` for different JSON
     types.,erase__IteratorType}
 
-    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
+    @sa see @ref erase(IteratorType, IteratorType) -- removes the elements in
     the given range
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    @sa see @ref erase(const typename object_t::key_type&) -- removes the element
     from an object at the given key
-    @sa @ref erase(const size_type) -- removes the element from an array at
+    @sa see @ref erase(const size_type) -- removes the element from an array at
     the given index
 
     @since version 1.0.0
     */
-    template<class IteratorType, typename std::enable_if<
-                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
-                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
-             = 0>
+    template < class IteratorType, typename std::enable_if <
+                   std::is_same<IteratorType, typename basic_json_t::iterator>::value ||
+                   std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int >::type
+               = 0 >
     IteratorType erase(IteratorType pos)
     {
         // make sure iterator fits the current value
-        if (JSON_UNLIKELY(this != pos.m_object))
+        if (JSON_HEDLEY_UNLIKELY(this != pos.m_object))
         {
-            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value", *this));
         }
 
         IteratorType result = end();
@@ -16016,10 +21741,11 @@ class basic_json
             case value_t::number_integer:
             case value_t::number_unsigned:
             case value_t::string:
+            case value_t::binary:
             {
-                if (JSON_UNLIKELY(not pos.m_it.primitive_iterator.is_begin()))
+                if (JSON_HEDLEY_UNLIKELY(!pos.m_it.primitive_iterator.is_begin()))
                 {
-                    JSON_THROW(invalid_iterator::create(205, "iterator out of range"));
+                    JSON_THROW(invalid_iterator::create(205, "iterator out of range", *this));
                 }
 
                 if (is_string())
@@ -16029,6 +21755,13 @@ class basic_json
                     std::allocator_traits<decltype(alloc)>::deallocate(alloc, m_value.string, 1);
                     m_value.string = nullptr;
                 }
+                else if (is_binary())
+                {
+                    AllocatorType<binary_t> alloc;
+                    std::allocator_traits<decltype(alloc)>::destroy(alloc, m_value.binary);
+                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, m_value.binary, 1);
+                    m_value.binary = nullptr;
+                }
 
                 m_type = value_t::null;
                 assert_invariant();
@@ -16047,8 +21780,10 @@ class basic_json
                 break;
             }
 
+            case value_t::null:
+            case value_t::discarded:
             default:
-                JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
+                JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name()), *this));
         }
 
         return result;
@@ -16086,30 +21821,30 @@ class basic_json
     - objects: `log(size()) + std::distance(first, last)`
     - arrays: linear in the distance between @a first and @a last, plus linear
       in the distance between @a last and end of the container
-    - strings: linear in the length of the string
+    - strings and binary: linear in the length of the member
     - other types: constant
 
     @liveexample{The example shows the result of `erase()` for different JSON
     types.,erase__IteratorType_IteratorType}
 
-    @sa @ref erase(IteratorType) -- removes the element at a given position
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    @sa see @ref erase(IteratorType) -- removes the element at a given position
+    @sa see @ref erase(const typename object_t::key_type&) -- removes the element
     from an object at the given key
-    @sa @ref erase(const size_type) -- removes the element from an array at
+    @sa see @ref erase(const size_type) -- removes the element from an array at
     the given index
 
     @since version 1.0.0
     */
-    template<class IteratorType, typename std::enable_if<
-                 std::is_same<IteratorType, typename basic_json_t::iterator>::value or
-                 std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type
-             = 0>
+    template < class IteratorType, typename std::enable_if <
+                   std::is_same<IteratorType, typename basic_json_t::iterator>::value ||
+                   std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int >::type
+               = 0 >
     IteratorType erase(IteratorType first, IteratorType last)
     {
         // make sure iterator fits the current value
-        if (JSON_UNLIKELY(this != first.m_object or this != last.m_object))
+        if (JSON_HEDLEY_UNLIKELY(this != first.m_object || this != last.m_object))
         {
-            JSON_THROW(invalid_iterator::create(203, "iterators do not fit current value"));
+            JSON_THROW(invalid_iterator::create(203, "iterators do not fit current value", *this));
         }
 
         IteratorType result = end();
@@ -16121,11 +21856,12 @@ class basic_json
             case value_t::number_integer:
             case value_t::number_unsigned:
             case value_t::string:
+            case value_t::binary:
             {
-                if (JSON_LIKELY(not first.m_it.primitive_iterator.is_begin()
-                                or not last.m_it.primitive_iterator.is_end()))
+                if (JSON_HEDLEY_LIKELY(!first.m_it.primitive_iterator.is_begin()
+                                       || !last.m_it.primitive_iterator.is_end()))
                 {
-                    JSON_THROW(invalid_iterator::create(204, "iterators out of range"));
+                    JSON_THROW(invalid_iterator::create(204, "iterators out of range", *this));
                 }
 
                 if (is_string())
@@ -16135,6 +21871,13 @@ class basic_json
                     std::allocator_traits<decltype(alloc)>::deallocate(alloc, m_value.string, 1);
                     m_value.string = nullptr;
                 }
+                else if (is_binary())
+                {
+                    AllocatorType<binary_t> alloc;
+                    std::allocator_traits<decltype(alloc)>::destroy(alloc, m_value.binary);
+                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, m_value.binary, 1);
+                    m_value.binary = nullptr;
+                }
 
                 m_type = value_t::null;
                 assert_invariant();
@@ -16155,8 +21898,10 @@ class basic_json
                 break;
             }
 
+            case value_t::null:
+            case value_t::discarded:
             default:
-                JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
+                JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name()), *this));
         }
 
         return result;
@@ -16183,10 +21928,10 @@ class basic_json
 
     @liveexample{The example shows the effect of `erase()`.,erase__key_type}
 
-    @sa @ref erase(IteratorType) -- removes the element at a given position
-    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
+    @sa see @ref erase(IteratorType) -- removes the element at a given position
+    @sa see @ref erase(IteratorType, IteratorType) -- removes the elements in
     the given range
-    @sa @ref erase(const size_type) -- removes the element from an array at
+    @sa see @ref erase(const size_type) -- removes the element from an array at
     the given index
 
     @since version 1.0.0
@@ -16194,12 +21939,12 @@ class basic_json
     size_type erase(const typename object_t::key_type& key)
     {
         // this erase only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
             return m_value.object->erase(key);
         }
 
-        JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
+        JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -16218,10 +21963,10 @@ class basic_json
 
     @liveexample{The example shows the effect of `erase()`.,erase__size_type}
 
-    @sa @ref erase(IteratorType) -- removes the element at a given position
-    @sa @ref erase(IteratorType, IteratorType) -- removes the elements in
+    @sa see @ref erase(IteratorType) -- removes the element at a given position
+    @sa see @ref erase(IteratorType, IteratorType) -- removes the elements in
     the given range
-    @sa @ref erase(const typename object_t::key_type&) -- removes the element
+    @sa see @ref erase(const typename object_t::key_type&) -- removes the element
     from an object at the given key
 
     @since version 1.0.0
@@ -16229,18 +21974,18 @@ class basic_json
     void erase(const size_type idx)
     {
         // this erase only works for arrays
-        if (JSON_LIKELY(is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
         {
-            if (JSON_UNLIKELY(idx >= size()))
+            if (JSON_HEDLEY_UNLIKELY(idx >= size()))
             {
-                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
+                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range", *this));
             }
 
             m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx));
         }
         else
         {
-            JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(307, "cannot use erase() with " + std::string(type_name()), *this));
         }
     }
 
@@ -16274,6 +22019,8 @@ class basic_json
 
     @liveexample{The example shows how `find()` is used.,find__key_type}
 
+    @sa see @ref contains(KeyT&&) const -- checks whether a key exists
+
     @since version 1.0.0
     */
     template<typename KeyT>
@@ -16334,6 +22081,69 @@ class basic_json
         return is_object() ? m_value.object->count(std::forward<KeyT>(key)) : 0;
     }
 
+    /*!
+    @brief check the existence of an element in a JSON object
+
+    Check whether an element exists in a JSON object with key equivalent to
+    @a key. If the element is not found or the JSON value is not an object,
+    false is returned.
+
+    @note This method always returns false when executed on a JSON type
+          that is not an object.
+
+    @param[in] key key value to check its existence.
+
+    @return true if an element with specified @a key exists. If no such
+    element with such key is found or the JSON value is not an object,
+    false is returned.
+
+    @complexity Logarithmic in the size of the JSON object.
+
+    @liveexample{The following code shows an example for `contains()`.,contains}
+
+    @sa see @ref find(KeyT&&) -- returns an iterator to an object element
+    @sa see @ref contains(const json_pointer&) const -- checks the existence for a JSON pointer
+
+    @since version 3.6.0
+    */
+    template < typename KeyT, typename std::enable_if <
+                   !std::is_same<typename std::decay<KeyT>::type, json_pointer>::value, int >::type = 0 >
+    bool contains(KeyT && key) const
+    {
+        return is_object() && m_value.object->find(std::forward<KeyT>(key)) != m_value.object->end();
+    }
+
+    /*!
+    @brief check the existence of an element in a JSON object given a JSON pointer
+
+    Check whether the given JSON pointer @a ptr can be resolved in the current
+    JSON value.
+
+    @note This method can be executed on any JSON value type.
+
+    @param[in] ptr JSON pointer to check its existence.
+
+    @return true if the JSON pointer can be resolved to a stored value, false
+    otherwise.
+
+    @post If `j.contains(ptr)` returns true, it is safe to call `j[ptr]`.
+
+    @throw parse_error.106   if an array index begins with '0'
+    @throw parse_error.109   if an array index was not a number
+
+    @complexity Logarithmic in the size of the JSON object.
+
+    @liveexample{The following code shows an example for `contains()`.,contains_json_pointer}
+
+    @sa see @ref contains(KeyT &&) const -- checks the existence of a key
+
+    @since version 3.7.0
+    */
+    bool contains(const json_pointer& ptr) const
+    {
+        return ptr.contains(this);
+    }
+
     /// @}
 
 
@@ -16362,9 +22172,9 @@ class basic_json
 
     @liveexample{The following code shows an example for `begin()`.,begin}
 
-    @sa @ref cbegin() -- returns a const iterator to the beginning
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref cend() -- returns a const iterator to the end
+    @sa see @ref cbegin() -- returns a const iterator to the beginning
+    @sa see @ref end() -- returns an iterator to the end
+    @sa see @ref cend() -- returns a const iterator to the end
 
     @since version 1.0.0
     */
@@ -16402,9 +22212,9 @@ class basic_json
 
     @liveexample{The following code shows an example for `cbegin()`.,cbegin}
 
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref cend() -- returns a const iterator to the end
+    @sa see @ref begin() -- returns an iterator to the beginning
+    @sa see @ref end() -- returns an iterator to the end
+    @sa see @ref cend() -- returns a const iterator to the end
 
     @since version 1.0.0
     */
@@ -16433,9 +22243,9 @@ class basic_json
 
     @liveexample{The following code shows an example for `end()`.,end}
 
-    @sa @ref cend() -- returns a const iterator to the end
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref cbegin() -- returns a const iterator to the beginning
+    @sa see @ref cend() -- returns a const iterator to the end
+    @sa see @ref begin() -- returns an iterator to the beginning
+    @sa see @ref cbegin() -- returns a const iterator to the beginning
 
     @since version 1.0.0
     */
@@ -16473,9 +22283,9 @@ class basic_json
 
     @liveexample{The following code shows an example for `cend()`.,cend}
 
-    @sa @ref end() -- returns an iterator to the end
-    @sa @ref begin() -- returns an iterator to the beginning
-    @sa @ref cbegin() -- returns a const iterator to the beginning
+    @sa see @ref end() -- returns an iterator to the end
+    @sa see @ref begin() -- returns an iterator to the beginning
+    @sa see @ref cbegin() -- returns a const iterator to the beginning
 
     @since version 1.0.0
     */
@@ -16503,9 +22313,9 @@ class basic_json
 
     @liveexample{The following code shows an example for `rbegin()`.,rbegin}
 
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref crend() -- returns a const reverse iterator to the end
+    @sa see @ref crbegin() -- returns a const reverse iterator to the beginning
+    @sa see @ref rend() -- returns a reverse iterator to the end
+    @sa see @ref crend() -- returns a const reverse iterator to the end
 
     @since version 1.0.0
     */
@@ -16540,9 +22350,9 @@ class basic_json
 
     @liveexample{The following code shows an example for `rend()`.,rend}
 
-    @sa @ref crend() -- returns a const reverse iterator to the end
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+    @sa see @ref crend() -- returns a const reverse iterator to the end
+    @sa see @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa see @ref crbegin() -- returns a const reverse iterator to the beginning
 
     @since version 1.0.0
     */
@@ -16577,9 +22387,9 @@ class basic_json
 
     @liveexample{The following code shows an example for `crbegin()`.,crbegin}
 
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref crend() -- returns a const reverse iterator to the end
+    @sa see @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa see @ref rend() -- returns a reverse iterator to the end
+    @sa see @ref crend() -- returns a const reverse iterator to the end
 
     @since version 1.0.0
     */
@@ -16606,9 +22416,9 @@ class basic_json
 
     @liveexample{The following code shows an example for `crend()`.,crend}
 
-    @sa @ref rend() -- returns a reverse iterator to the end
-    @sa @ref rbegin() -- returns a reverse iterator to the beginning
-    @sa @ref crbegin() -- returns a const reverse iterator to the beginning
+    @sa see @ref rend() -- returns a reverse iterator to the end
+    @sa see @ref rbegin() -- returns a reverse iterator to the beginning
+    @sa see @ref crbegin() -- returns a const reverse iterator to the beginning
 
     @since version 1.0.0
     */
@@ -16675,7 +22485,7 @@ class basic_json
                 future 4.0.0 of the library. Please use @ref items() instead;
                 that is, replace `json::iterator_wrapper(j)` with `j.items()`.
     */
-    JSON_DEPRECATED
+    JSON_HEDLEY_DEPRECATED_FOR(3.1.0, items())
     static iteration_proxy<iterator> iterator_wrapper(reference ref) noexcept
     {
         return ref.items();
@@ -16684,7 +22494,7 @@ class basic_json
     /*!
     @copydoc iterator_wrapper(reference)
     */
-    JSON_DEPRECATED
+    JSON_HEDLEY_DEPRECATED_FOR(3.1.0, items())
     static iteration_proxy<const_iterator> iterator_wrapper(const_reference ref) noexcept
     {
         return ref.items();
@@ -16741,6 +22551,11 @@ class basic_json
           element as string (see example). For primitive types (e.g., numbers),
           `key()` returns an empty string.
 
+    @warning Using `items()` on temporary objects is dangerous. Make sure the
+             object's lifetime exeeds the iteration. See
+             <https://github.com/nlohmann/json/issues/2040> for more
+             information.
+
     @return iteration proxy object wrapping @a ref with an interface to use in
             range-based for loops
 
@@ -16789,6 +22604,7 @@ class basic_json
             boolean     | `false`
             string      | `false`
             number      | `false`
+            binary      | `false`
             object      | result of function `object_t::empty()`
             array       | result of function `array_t::empty()`
 
@@ -16813,7 +22629,7 @@ class basic_json
     - The complexity is constant.
     - Has the semantics of `begin() == end()`.
 
-    @sa @ref size() -- returns the number of elements
+    @sa see @ref size() -- returns the number of elements
 
     @since version 1.0.0
     */
@@ -16839,6 +22655,13 @@ class basic_json
                 return m_value.object->empty();
             }
 
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
             default:
             {
                 // all other types are nonempty
@@ -16860,6 +22683,7 @@ class basic_json
             boolean     | `1`
             string      | `1`
             number      | `1`
+            binary      | `1`
             object      | result of function object_t::size()
             array       | result of function array_t::size()
 
@@ -16884,8 +22708,8 @@ class basic_json
     - The complexity is constant.
     - Has the semantics of `std::distance(begin(), end())`.
 
-    @sa @ref empty() -- checks whether the container is empty
-    @sa @ref max_size() -- returns the maximal number of elements
+    @sa see @ref empty() -- checks whether the container is empty
+    @sa see @ref max_size() -- returns the maximal number of elements
 
     @since version 1.0.0
     */
@@ -16911,6 +22735,13 @@ class basic_json
                 return m_value.object->size();
             }
 
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
             default:
             {
                 // all other types have size 1
@@ -16934,6 +22765,7 @@ class basic_json
             boolean     | `1` (same as `size()`)
             string      | `1` (same as `size()`)
             number      | `1` (same as `size()`)
+            binary      | `1` (same as `size()`)
             object      | result of function `object_t::max_size()`
             array       | result of function `array_t::max_size()`
 
@@ -16955,7 +22787,7 @@ class basic_json
     - Has the semantics of returning `b.size()` where `b` is the largest
       possible JSON value.
 
-    @sa @ref size() -- returns the number of elements
+    @sa see @ref size() -- returns the number of elements
 
     @since version 1.0.0
     */
@@ -16975,6 +22807,14 @@ class basic_json
                 return m_value.object->max_size();
             }
 
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
             default:
             {
                 // all other types have max_size() == size()
@@ -17006,6 +22846,7 @@ class basic_json
     boolean     | `false`
     string      | `""`
     number      | `0`
+    binary      | An empty byte vector
     object      | `{}`
     array       | `[]`
 
@@ -17024,7 +22865,7 @@ class basic_json
 
     @exceptionsafety No-throw guarantee: this function never throws exceptions.
 
-    @sa @ref basic_json(value_t) -- constructor that creates an object with the
+    @sa see @ref basic_json(value_t) -- constructor that creates an object with the
         same value than calling `clear()`
 
     @since version 1.0.0
@@ -17063,6 +22904,12 @@ class basic_json
                 break;
             }
 
+            case value_t::binary:
+            {
+                m_value.binary->clear();
+                break;
+            }
+
             case value_t::array:
             {
                 m_value.array->clear();
@@ -17075,6 +22922,8 @@ class basic_json
                 break;
             }
 
+            case value_t::null:
+            case value_t::discarded:
             default:
                 break;
         }
@@ -17103,9 +22952,9 @@ class basic_json
     void push_back(basic_json&& val)
     {
         // push_back only works for null objects or arrays
-        if (JSON_UNLIKELY(not(is_null() or is_array())))
+        if (JSON_HEDLEY_UNLIKELY(!(is_null() || is_array())))
         {
-            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name()), *this));
         }
 
         // transform null object into an array
@@ -17117,9 +22966,10 @@ class basic_json
         }
 
         // add element to array (move semantics)
+        const auto old_capacity = m_value.array->capacity();
         m_value.array->push_back(std::move(val));
-        // invalidate object
-        val.m_type = value_t::null;
+        set_parent(m_value.array->back(), old_capacity);
+        // if val is moved from, basic_json move constructor marks it null so we do not call the destructor
     }
 
     /*!
@@ -17139,9 +22989,9 @@ class basic_json
     void push_back(const basic_json& val)
     {
         // push_back only works for null objects or arrays
-        if (JSON_UNLIKELY(not(is_null() or is_array())))
+        if (JSON_HEDLEY_UNLIKELY(!(is_null() || is_array())))
         {
-            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name()), *this));
         }
 
         // transform null object into an array
@@ -17153,7 +23003,9 @@ class basic_json
         }
 
         // add element to array
+        const auto old_capacity = m_value.array->capacity();
         m_value.array->push_back(val);
+        set_parent(m_value.array->back(), old_capacity);
     }
 
     /*!
@@ -17189,9 +23041,9 @@ class basic_json
     void push_back(const typename object_t::value_type& val)
     {
         // push_back only works for null objects or objects
-        if (JSON_UNLIKELY(not(is_null() or is_object())))
+        if (JSON_HEDLEY_UNLIKELY(!(is_null() || is_object())))
         {
-            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(308, "cannot use push_back() with " + std::string(type_name()), *this));
         }
 
         // transform null object into an object
@@ -17202,8 +23054,9 @@ class basic_json
             assert_invariant();
         }
 
-        // add element to array
-        m_value.object->insert(val);
+        // add element to object
+        auto res = m_value.object->insert(val);
+        set_parent(res.first->second);
     }
 
     /*!
@@ -17243,7 +23096,7 @@ class basic_json
     */
     void push_back(initializer_list_t init)
     {
-        if (is_object() and init.size() == 2 and (*init.begin())->is_string())
+        if (is_object() && init.size() == 2 && (*init.begin())->is_string())
         {
             basic_json&& key = init.begin()->moved_or_copied();
             push_back(typename object_t::value_type(
@@ -17275,6 +23128,8 @@ class basic_json
     @param[in] args arguments to forward to a constructor of @ref basic_json
     @tparam Args compatible types to create a @ref basic_json object
 
+    @return reference to the inserted element
+
     @throw type_error.311 when called on a type other than JSON array or
     null; example: `"cannot use emplace_back() with number"`
 
@@ -17284,15 +23139,15 @@ class basic_json
     elements to a JSON array. Note how the `null` value was silently converted
     to a JSON array.,emplace_back}
 
-    @since version 2.0.8
+    @since version 2.0.8, returns reference since 3.7.0
     */
     template<class... Args>
-    void emplace_back(Args&& ... args)
+    reference emplace_back(Args&& ... args)
     {
         // emplace_back only works for null objects or arrays
-        if (JSON_UNLIKELY(not(is_null() or is_array())))
+        if (JSON_HEDLEY_UNLIKELY(!(is_null() || is_array())))
         {
-            JSON_THROW(type_error::create(311, "cannot use emplace_back() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(311, "cannot use emplace_back() with " + std::string(type_name()), *this));
         }
 
         // transform null object into an array
@@ -17304,7 +23159,9 @@ class basic_json
         }
 
         // add element to array (perfect forwarding)
+        const auto old_capacity = m_value.array->capacity();
         m_value.array->emplace_back(std::forward<Args>(args)...);
+        return set_parent(m_value.array->back(), old_capacity);
     }
 
     /*!
@@ -17338,9 +23195,9 @@ class basic_json
     std::pair<iterator, bool> emplace(Args&& ... args)
     {
         // emplace only works for null objects or arrays
-        if (JSON_UNLIKELY(not(is_null() or is_object())))
+        if (JSON_HEDLEY_UNLIKELY(!(is_null() || is_object())))
         {
-            JSON_THROW(type_error::create(311, "cannot use emplace() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(311, "cannot use emplace() with " + std::string(type_name()), *this));
         }
 
         // transform null object into an object
@@ -17353,6 +23210,8 @@ class basic_json
 
         // add element to array (perfect forwarding)
         auto res = m_value.object->emplace(std::forward<Args>(args)...);
+        set_parent(res.first->second);
+
         // create result iterator and set iterator to the result of emplace
         auto it = begin();
         it.m_it.object_iterator = res.first;
@@ -17368,7 +23227,7 @@ class basic_json
     iterator insert_iterator(const_iterator pos, Args&& ... args)
     {
         iterator result(this);
-        assert(m_value.array != nullptr);
+        JSON_ASSERT(m_value.array != nullptr);
 
         auto insert_pos = std::distance(m_value.array->begin(), pos.m_it.array_iterator);
         m_value.array->insert(pos.m_it.array_iterator, std::forward<Args>(args)...);
@@ -17378,6 +23237,7 @@ class basic_json
         // result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val);
         // but the return value of insert is missing in GCC 4.8, so it is written this way instead.
 
+        set_parents();
         return result;
     }
 
@@ -17406,19 +23266,19 @@ class basic_json
     iterator insert(const_iterator pos, const basic_json& val)
     {
         // insert only works for arrays
-        if (JSON_LIKELY(is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
         {
             // check if iterator pos fits to this JSON value
-            if (JSON_UNLIKELY(pos.m_object != this))
+            if (JSON_HEDLEY_UNLIKELY(pos.m_object != this))
             {
-                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value", *this));
             }
 
             // insert to array and return iterator
             return insert_iterator(pos, val);
         }
 
-        JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+        JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -17457,19 +23317,19 @@ class basic_json
     iterator insert(const_iterator pos, size_type cnt, const basic_json& val)
     {
         // insert only works for arrays
-        if (JSON_LIKELY(is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
         {
             // check if iterator pos fits to this JSON value
-            if (JSON_UNLIKELY(pos.m_object != this))
+            if (JSON_HEDLEY_UNLIKELY(pos.m_object != this))
             {
-                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+                JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value", *this));
             }
 
             // insert to array and return iterator
             return insert_iterator(pos, cnt, val);
         }
 
-        JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+        JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name()), *this));
     }
 
     /*!
@@ -17505,26 +23365,26 @@ class basic_json
     iterator insert(const_iterator pos, const_iterator first, const_iterator last)
     {
         // insert only works for arrays
-        if (JSON_UNLIKELY(not is_array()))
+        if (JSON_HEDLEY_UNLIKELY(!is_array()))
         {
-            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name()), *this));
         }
 
         // check if iterator pos fits to this JSON value
-        if (JSON_UNLIKELY(pos.m_object != this))
+        if (JSON_HEDLEY_UNLIKELY(pos.m_object != this))
         {
-            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value", *this));
         }
 
         // check if range iterators belong to the same JSON object
-        if (JSON_UNLIKELY(first.m_object != last.m_object))
+        if (JSON_HEDLEY_UNLIKELY(first.m_object != last.m_object))
         {
-            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
+            JSON_THROW(invalid_iterator::create(210, "iterators do not fit", *this));
         }
 
-        if (JSON_UNLIKELY(first.m_object == this))
+        if (JSON_HEDLEY_UNLIKELY(first.m_object == this))
         {
-            JSON_THROW(invalid_iterator::create(211, "passed iterators may not belong to container"));
+            JSON_THROW(invalid_iterator::create(211, "passed iterators may not belong to container", *this));
         }
 
         // insert to array and return iterator
@@ -17558,15 +23418,15 @@ class basic_json
     iterator insert(const_iterator pos, initializer_list_t ilist)
     {
         // insert only works for arrays
-        if (JSON_UNLIKELY(not is_array()))
+        if (JSON_HEDLEY_UNLIKELY(!is_array()))
         {
-            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name()), *this));
         }
 
         // check if iterator pos fits to this JSON value
-        if (JSON_UNLIKELY(pos.m_object != this))
+        if (JSON_HEDLEY_UNLIKELY(pos.m_object != this))
         {
-            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value"));
+            JSON_THROW(invalid_iterator::create(202, "iterator does not fit current value", *this));
         }
 
         // insert to array and return iterator
@@ -17599,21 +23459,21 @@ class basic_json
     void insert(const_iterator first, const_iterator last)
     {
         // insert only works for objects
-        if (JSON_UNLIKELY(not is_object()))
+        if (JSON_HEDLEY_UNLIKELY(!is_object()))
         {
-            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(309, "cannot use insert() with " + std::string(type_name()), *this));
         }
 
         // check if range iterators belong to the same JSON object
-        if (JSON_UNLIKELY(first.m_object != last.m_object))
+        if (JSON_HEDLEY_UNLIKELY(first.m_object != last.m_object))
         {
-            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
+            JSON_THROW(invalid_iterator::create(210, "iterators do not fit", *this));
         }
 
         // passed iterators must belong to objects
-        if (JSON_UNLIKELY(not first.m_object->is_object()))
+        if (JSON_HEDLEY_UNLIKELY(!first.m_object->is_object()))
         {
-            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects"));
+            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects", *this));
         }
 
         m_value.object->insert(first.m_it.object_iterator, last.m_it.object_iterator);
@@ -17648,18 +23508,21 @@ class basic_json
             assert_invariant();
         }
 
-        if (JSON_UNLIKELY(not is_object()))
+        if (JSON_HEDLEY_UNLIKELY(!is_object()))
         {
-            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name()), *this));
         }
-        if (JSON_UNLIKELY(not j.is_object()))
+        if (JSON_HEDLEY_UNLIKELY(!j.is_object()))
         {
-            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(j.type_name())));
+            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(j.type_name()), *this));
         }
 
         for (auto it = j.cbegin(); it != j.cend(); ++it)
         {
             m_value.object->operator[](it.key()) = it.value();
+#if JSON_DIAGNOSTICS
+            m_value.object->operator[](it.key()).m_parent = this;
+#endif
         }
     }
 
@@ -17699,27 +23562,30 @@ class basic_json
             assert_invariant();
         }
 
-        if (JSON_UNLIKELY(not is_object()))
+        if (JSON_HEDLEY_UNLIKELY(!is_object()))
         {
-            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name()), *this));
         }
 
         // check if range iterators belong to the same JSON object
-        if (JSON_UNLIKELY(first.m_object != last.m_object))
+        if (JSON_HEDLEY_UNLIKELY(first.m_object != last.m_object))
         {
-            JSON_THROW(invalid_iterator::create(210, "iterators do not fit"));
+            JSON_THROW(invalid_iterator::create(210, "iterators do not fit", *this));
         }
 
         // passed iterators must belong to objects
-        if (JSON_UNLIKELY(not first.m_object->is_object()
-                          or not last.m_object->is_object()))
+        if (JSON_HEDLEY_UNLIKELY(!first.m_object->is_object()
+                                 || !last.m_object->is_object()))
         {
-            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects"));
+            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to objects", *this));
         }
 
         for (auto it = first; it != last; ++it)
         {
             m_value.object->operator[](it.key()) = it.value();
+#if JSON_DIAGNOSTICS
+            m_value.object->operator[](it.key()).m_parent = this;
+#endif
         }
     }
 
@@ -17741,20 +23607,51 @@ class basic_json
     @since version 1.0.0
     */
     void swap(reference other) noexcept (
-        std::is_nothrow_move_constructible<value_t>::value and
-        std::is_nothrow_move_assignable<value_t>::value and
-        std::is_nothrow_move_constructible<json_value>::value and
+        std::is_nothrow_move_constructible<value_t>::value&&
+        std::is_nothrow_move_assignable<value_t>::value&&
+        std::is_nothrow_move_constructible<json_value>::value&&
         std::is_nothrow_move_assignable<json_value>::value
     )
     {
         std::swap(m_type, other.m_type);
         std::swap(m_value, other.m_value);
+
+        set_parents();
+        other.set_parents();
         assert_invariant();
     }
 
     /*!
     @brief exchanges the values
 
+    Exchanges the contents of the JSON value from @a left with those of @a right. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated. implemented as a friend function callable via ADL.
+
+    @param[in,out] left JSON value to exchange the contents with
+    @param[in,out] right JSON value to exchange the contents with
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how JSON values can be swapped with
+    `swap()`.,swap__reference}
+
+    @since version 1.0.0
+    */
+    friend void swap(reference left, reference right) noexcept (
+        std::is_nothrow_move_constructible<value_t>::value&&
+        std::is_nothrow_move_assignable<value_t>::value&&
+        std::is_nothrow_move_constructible<json_value>::value&&
+        std::is_nothrow_move_assignable<json_value>::value
+    )
+    {
+        left.swap(right);
+    }
+
+    /*!
+    @brief exchanges the values
+
     Exchanges the contents of a JSON array with those of @a other. Does not
     invoke any move, copy, or swap operations on individual elements. All
     iterators and references remain valid. The past-the-end iterator is
@@ -17772,16 +23669,16 @@ class basic_json
 
     @since version 1.0.0
     */
-    void swap(array_t& other)
+    void swap(array_t& other) // NOLINT(bugprone-exception-escape)
     {
         // swap only works for arrays
-        if (JSON_LIKELY(is_array()))
+        if (JSON_HEDLEY_LIKELY(is_array()))
         {
             std::swap(*(m_value.array), other);
         }
         else
         {
-            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name()), *this));
         }
     }
 
@@ -17805,16 +23702,16 @@ class basic_json
 
     @since version 1.0.0
     */
-    void swap(object_t& other)
+    void swap(object_t& other) // NOLINT(bugprone-exception-escape)
     {
         // swap only works for objects
-        if (JSON_LIKELY(is_object()))
+        if (JSON_HEDLEY_LIKELY(is_object()))
         {
             std::swap(*(m_value.object), other);
         }
         else
         {
-            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name()), *this));
         }
     }
 
@@ -17838,16 +23735,63 @@ class basic_json
 
     @since version 1.0.0
     */
-    void swap(string_t& other)
+    void swap(string_t& other) // NOLINT(bugprone-exception-escape)
     {
         // swap only works for strings
-        if (JSON_LIKELY(is_string()))
+        if (JSON_HEDLEY_LIKELY(is_string()))
         {
             std::swap(*(m_value.string), other);
         }
         else
         {
-            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name())));
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name()), *this));
+        }
+    }
+
+    /*!
+    @brief exchanges the values
+
+    Exchanges the contents of a JSON string with those of @a other. Does not
+    invoke any move, copy, or swap operations on individual elements. All
+    iterators and references remain valid. The past-the-end iterator is
+    invalidated.
+
+    @param[in,out] other binary to exchange the contents with
+
+    @throw type_error.310 when JSON value is not a string; example: `"cannot
+    use swap() with boolean"`
+
+    @complexity Constant.
+
+    @liveexample{The example below shows how strings can be swapped with
+    `swap()`.,swap__binary_t}
+
+    @since version 3.8.0
+    */
+    void swap(binary_t& other) // NOLINT(bugprone-exception-escape)
+    {
+        // swap only works for strings
+        if (JSON_HEDLEY_LIKELY(is_binary()))
+        {
+            std::swap(*(m_value.binary), other);
+        }
+        else
+        {
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name()), *this));
+        }
+    }
+
+    /// @copydoc swap(binary_t&)
+    void swap(typename binary_t::container_type& other) // NOLINT(bugprone-exception-escape)
+    {
+        // swap only works for strings
+        if (JSON_HEDLEY_LIKELY(is_binary()))
+        {
+            std::swap(*(m_value.binary), other);
+        }
+        else
+        {
+            JSON_THROW(type_error::create(310, "cannot use swap() with " + std::string(type_name()), *this));
         }
     }
 
@@ -17869,13 +23813,13 @@ class basic_json
       their stored values are the same according to their respective
       `operator==`.
     - Integer and floating-point numbers are automatically converted before
-      comparison. Note than two NaN values are always treated as unequal.
+      comparison. Note that two NaN values are always treated as unequal.
     - Two JSON null values are equal.
 
     @note Floating-point inside JSON values numbers are compared with
     `json::number_float_t::operator==` which is `double::operator==` by
     default. To compare floating-point while respecting an epsilon, an alternative
-    [comparison function](https://github.com/mariokonrad/marnav/blob/master/src/marnav/math/floatingpoint.hpp#L34-#L39)
+    [comparison function](https://github.com/mariokonrad/marnav/blob/master/include/marnav/math/floatingpoint.hpp#L34-#L39)
     could be used, for instance
     @code {.cpp}
     template<typename T, typename = typename std::enable_if<std::is_floating_point<T>::value, T>::type>
@@ -17884,6 +23828,22 @@ class basic_json
         return std::abs(a - b) <= epsilon;
     }
     @endcode
+    Or you can self-defined operator equal function like this:
+    @code {.cpp}
+    bool my_equal(const_reference lhs, const_reference rhs) {
+    const auto lhs_type lhs.type();
+    const auto rhs_type rhs.type();
+    if (lhs_type == rhs_type) {
+        switch(lhs_type)
+            // self_defined case
+            case value_t::number_float:
+                return std::abs(lhs - rhs) <= std::numeric_limits<float>::epsilon();
+            // other cases remain the same with the original
+            ...
+    }
+    ...
+    }
+    @endcode
 
     @note NaN values never compare equal to themselves or to other NaN values.
 
@@ -17902,6 +23862,10 @@ class basic_json
     */
     friend bool operator==(const_reference lhs, const_reference rhs) noexcept
     {
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
         const auto lhs_type = lhs.type();
         const auto rhs_type = rhs.type();
 
@@ -17910,59 +23874,66 @@ class basic_json
             switch (lhs_type)
             {
                 case value_t::array:
-                    return (*lhs.m_value.array == *rhs.m_value.array);
+                    return *lhs.m_value.array == *rhs.m_value.array;
 
                 case value_t::object:
-                    return (*lhs.m_value.object == *rhs.m_value.object);
+                    return *lhs.m_value.object == *rhs.m_value.object;
 
                 case value_t::null:
                     return true;
 
                 case value_t::string:
-                    return (*lhs.m_value.string == *rhs.m_value.string);
+                    return *lhs.m_value.string == *rhs.m_value.string;
 
                 case value_t::boolean:
-                    return (lhs.m_value.boolean == rhs.m_value.boolean);
+                    return lhs.m_value.boolean == rhs.m_value.boolean;
 
                 case value_t::number_integer:
-                    return (lhs.m_value.number_integer == rhs.m_value.number_integer);
+                    return lhs.m_value.number_integer == rhs.m_value.number_integer;
 
                 case value_t::number_unsigned:
-                    return (lhs.m_value.number_unsigned == rhs.m_value.number_unsigned);
+                    return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned;
 
                 case value_t::number_float:
-                    return (lhs.m_value.number_float == rhs.m_value.number_float);
+                    return lhs.m_value.number_float == rhs.m_value.number_float;
 
+                case value_t::binary:
+                    return *lhs.m_value.binary == *rhs.m_value.binary;
+
+                case value_t::discarded:
                 default:
                     return false;
             }
         }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_float)
         {
-            return (static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float);
+            return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float;
         }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        else if (lhs_type == value_t::number_float && rhs_type == value_t::number_integer)
         {
-            return (lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer));
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer);
         }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_float)
         {
-            return (static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float);
+            return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float;
         }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        else if (lhs_type == value_t::number_float && rhs_type == value_t::number_unsigned)
         {
-            return (lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned));
+            return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned);
         }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_integer)
         {
-            return (static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer);
+            return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer;
         }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_unsigned)
         {
-            return (lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned));
+            return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned);
         }
 
         return false;
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
     }
 
     /*!
@@ -17971,9 +23942,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator==(const_reference lhs, const ScalarType rhs) noexcept
+    friend bool operator==(const_reference lhs, ScalarType rhs) noexcept
     {
-        return (lhs == basic_json(rhs));
+        return lhs == basic_json(rhs);
     }
 
     /*!
@@ -17982,9 +23953,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator==(const ScalarType lhs, const_reference rhs) noexcept
+    friend bool operator==(ScalarType lhs, const_reference rhs) noexcept
     {
-        return (basic_json(lhs) == rhs);
+        return basic_json(lhs) == rhs;
     }
 
     /*!
@@ -18007,7 +23978,7 @@ class basic_json
     */
     friend bool operator!=(const_reference lhs, const_reference rhs) noexcept
     {
-        return not (lhs == rhs);
+        return !(lhs == rhs);
     }
 
     /*!
@@ -18016,9 +23987,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator!=(const_reference lhs, const ScalarType rhs) noexcept
+    friend bool operator!=(const_reference lhs, ScalarType rhs) noexcept
     {
-        return (lhs != basic_json(rhs));
+        return lhs != basic_json(rhs);
     }
 
     /*!
@@ -18027,9 +23998,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator!=(const ScalarType lhs, const_reference rhs) noexcept
+    friend bool operator!=(ScalarType lhs, const_reference rhs) noexcept
     {
-        return (basic_json(lhs) != rhs);
+        return basic_json(lhs) != rhs;
     }
 
     /*!
@@ -18068,54 +24039,60 @@ class basic_json
             switch (lhs_type)
             {
                 case value_t::array:
+                    // note parentheses are necessary, see
+                    // https://github.com/nlohmann/json/issues/1530
                     return (*lhs.m_value.array) < (*rhs.m_value.array);
 
                 case value_t::object:
-                    return *lhs.m_value.object < *rhs.m_value.object;
+                    return (*lhs.m_value.object) < (*rhs.m_value.object);
 
                 case value_t::null:
                     return false;
 
                 case value_t::string:
-                    return *lhs.m_value.string < *rhs.m_value.string;
+                    return (*lhs.m_value.string) < (*rhs.m_value.string);
 
                 case value_t::boolean:
-                    return lhs.m_value.boolean < rhs.m_value.boolean;
+                    return (lhs.m_value.boolean) < (rhs.m_value.boolean);
 
                 case value_t::number_integer:
-                    return lhs.m_value.number_integer < rhs.m_value.number_integer;
+                    return (lhs.m_value.number_integer) < (rhs.m_value.number_integer);
 
                 case value_t::number_unsigned:
-                    return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned;
+                    return (lhs.m_value.number_unsigned) < (rhs.m_value.number_unsigned);
 
                 case value_t::number_float:
-                    return lhs.m_value.number_float < rhs.m_value.number_float;
+                    return (lhs.m_value.number_float) < (rhs.m_value.number_float);
+
+                case value_t::binary:
+                    return (*lhs.m_value.binary) < (*rhs.m_value.binary);
 
+                case value_t::discarded:
                 default:
                     return false;
             }
         }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float)
+        else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_float)
         {
             return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float;
         }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer)
+        else if (lhs_type == value_t::number_float && rhs_type == value_t::number_integer)
         {
             return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer);
         }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float)
+        else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_float)
         {
             return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float;
         }
-        else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned)
+        else if (lhs_type == value_t::number_float && rhs_type == value_t::number_unsigned)
         {
             return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned);
         }
-        else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned)
+        else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_unsigned)
         {
             return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned);
         }
-        else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer)
+        else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_integer)
         {
             return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer;
         }
@@ -18132,9 +24109,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator<(const_reference lhs, const ScalarType rhs) noexcept
+    friend bool operator<(const_reference lhs, ScalarType rhs) noexcept
     {
-        return (lhs < basic_json(rhs));
+        return lhs < basic_json(rhs);
     }
 
     /*!
@@ -18143,9 +24120,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator<(const ScalarType lhs, const_reference rhs) noexcept
+    friend bool operator<(ScalarType lhs, const_reference rhs) noexcept
     {
-        return (basic_json(lhs) < rhs);
+        return basic_json(lhs) < rhs;
     }
 
     /*!
@@ -18169,7 +24146,7 @@ class basic_json
     */
     friend bool operator<=(const_reference lhs, const_reference rhs) noexcept
     {
-        return not (rhs < lhs);
+        return !(rhs < lhs);
     }
 
     /*!
@@ -18178,9 +24155,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator<=(const_reference lhs, const ScalarType rhs) noexcept
+    friend bool operator<=(const_reference lhs, ScalarType rhs) noexcept
     {
-        return (lhs <= basic_json(rhs));
+        return lhs <= basic_json(rhs);
     }
 
     /*!
@@ -18189,9 +24166,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator<=(const ScalarType lhs, const_reference rhs) noexcept
+    friend bool operator<=(ScalarType lhs, const_reference rhs) noexcept
     {
-        return (basic_json(lhs) <= rhs);
+        return basic_json(lhs) <= rhs;
     }
 
     /*!
@@ -18215,7 +24192,7 @@ class basic_json
     */
     friend bool operator>(const_reference lhs, const_reference rhs) noexcept
     {
-        return not (lhs <= rhs);
+        return !(lhs <= rhs);
     }
 
     /*!
@@ -18224,9 +24201,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator>(const_reference lhs, const ScalarType rhs) noexcept
+    friend bool operator>(const_reference lhs, ScalarType rhs) noexcept
     {
-        return (lhs > basic_json(rhs));
+        return lhs > basic_json(rhs);
     }
 
     /*!
@@ -18235,9 +24212,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator>(const ScalarType lhs, const_reference rhs) noexcept
+    friend bool operator>(ScalarType lhs, const_reference rhs) noexcept
     {
-        return (basic_json(lhs) > rhs);
+        return basic_json(lhs) > rhs;
     }
 
     /*!
@@ -18261,7 +24238,7 @@ class basic_json
     */
     friend bool operator>=(const_reference lhs, const_reference rhs) noexcept
     {
-        return not (lhs < rhs);
+        return !(lhs < rhs);
     }
 
     /*!
@@ -18270,9 +24247,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator>=(const_reference lhs, const ScalarType rhs) noexcept
+    friend bool operator>=(const_reference lhs, ScalarType rhs) noexcept
     {
-        return (lhs >= basic_json(rhs));
+        return lhs >= basic_json(rhs);
     }
 
     /*!
@@ -18281,9 +24258,9 @@ class basic_json
     */
     template<typename ScalarType, typename std::enable_if<
                  std::is_scalar<ScalarType>::value, int>::type = 0>
-    friend bool operator>=(const ScalarType lhs, const_reference rhs) noexcept
+    friend bool operator>=(ScalarType lhs, const_reference rhs) noexcept
     {
-        return (basic_json(lhs) >= rhs);
+        return basic_json(lhs) >= rhs;
     }
 
     /// @}
@@ -18294,7 +24271,7 @@ class basic_json
 
     /// @name serialization
     /// @{
-
+#ifndef JSON_NO_IO
     /*!
     @brief serialize to stream
 
@@ -18329,8 +24306,8 @@ class basic_json
     friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
     {
         // read width member and use it as indentation parameter if nonzero
-        const bool pretty_print = (o.width() > 0);
-        const auto indentation = (pretty_print ? o.width() : 0);
+        const bool pretty_print = o.width() > 0;
+        const auto indentation = pretty_print ? o.width() : 0;
 
         // reset width to 0 for subsequent calls to this stream
         o.width(0);
@@ -18349,12 +24326,12 @@ class basic_json
                 instead; that is, replace calls like `j >> o;` with `o << j;`.
     @since version 1.0.0; deprecated since version 3.0.0
     */
-    JSON_DEPRECATED
+    JSON_HEDLEY_DEPRECATED_FOR(3.0.0, operator<<(std::ostream&, const basic_json&))
     friend std::ostream& operator>>(const basic_json& j, std::ostream& o)
     {
         return o << j;
     }
-
+#endif  // JSON_NO_IO
     /// @}
 
 
@@ -18366,81 +24343,169 @@ class basic_json
     /// @{
 
     /*!
-    @brief deserialize from a compatible input
+    @brief deserialize from a compatible input
+
+    @tparam InputType A compatible input, for instance
+    - an std::istream object
+    - a FILE pointer
+    - a C-style array of characters
+    - a pointer to a null-terminated string of single byte characters
+    - an object obj for which begin(obj) and end(obj) produces a valid pair of
+      iterators.
+
+    @param[in] i  input to read from
+    @param[in] cb  a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+    @param[in] allow_exceptions  whether to throw exceptions in case of a
+    parse error (optional, true by default)
+    @param[in] ignore_comments  whether comments should be ignored and treated
+    like whitespace (true) or yield a parse error (true); (optional, false by
+    default)
+
+    @return deserialized JSON value; in case of a parse error and
+            @a allow_exceptions set to `false`, the return value will be
+            value_t::discarded.
+
+    @throw parse_error.101 if a parse error occurs; example: `""unexpected end
+    of input; expected string literal""`
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
+
+    @complexity Linear in the length of the input. The parser is a predictive
+    LL(1) parser. The complexity can be higher if the parser callback function
+    @a cb or reading from the input @a i has a super-linear complexity.
+
+    @note A UTF-8 byte order mark is silently ignored.
+
+    @liveexample{The example below demonstrates the `parse()` function reading
+    from an array.,parse__array__parser_callback_t}
+
+    @liveexample{The example below demonstrates the `parse()` function with
+    and without callback function.,parse__string__parser_callback_t}
+
+    @liveexample{The example below demonstrates the `parse()` function with
+    and without callback function.,parse__istream__parser_callback_t}
+
+    @liveexample{The example below demonstrates the `parse()` function reading
+    from a contiguous container.,parse__contiguouscontainer__parser_callback_t}
+
+    @since version 2.0.3 (contiguous containers); version 3.9.0 allowed to
+    ignore comments.
+    */
+    template<typename InputType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json parse(InputType&& i,
+                            const parser_callback_t cb = nullptr,
+                            const bool allow_exceptions = true,
+                            const bool ignore_comments = false)
+    {
+        basic_json result;
+        parser(detail::input_adapter(std::forward<InputType>(i)), cb, allow_exceptions, ignore_comments).parse(true, result);
+        return result;
+    }
+
+    /*!
+    @brief deserialize from a pair of character iterators
+
+    The value_type of the iterator must be a integral type with size of 1, 2 or
+    4 bytes, which will be interpreted respectively as UTF-8, UTF-16 and UTF-32.
+
+    @param[in] first iterator to start of character range
+    @param[in] last  iterator to end of character range
+    @param[in] cb  a parser callback function of type @ref parser_callback_t
+    which is used to control the deserialization by filtering unwanted values
+    (optional)
+    @param[in] allow_exceptions  whether to throw exceptions in case of a
+    parse error (optional, true by default)
+    @param[in] ignore_comments  whether comments should be ignored and treated
+    like whitespace (true) or yield a parse error (true); (optional, false by
+    default)
+
+    @return deserialized JSON value; in case of a parse error and
+            @a allow_exceptions set to `false`, the return value will be
+            value_t::discarded.
+
+    @throw parse_error.101 if a parse error occurs; example: `""unexpected end
+    of input; expected string literal""`
+    @throw parse_error.102 if to_unicode fails or surrogate error
+    @throw parse_error.103 if to_unicode fails
+    */
+    template<typename IteratorType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json parse(IteratorType first,
+                            IteratorType last,
+                            const parser_callback_t cb = nullptr,
+                            const bool allow_exceptions = true,
+                            const bool ignore_comments = false)
+    {
+        basic_json result;
+        parser(detail::input_adapter(std::move(first), std::move(last)), cb, allow_exceptions, ignore_comments).parse(true, result);
+        return result;
+    }
+
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, parse(ptr, ptr + len))
+    static basic_json parse(detail::span_input_adapter&& i,
+                            const parser_callback_t cb = nullptr,
+                            const bool allow_exceptions = true,
+                            const bool ignore_comments = false)
+    {
+        basic_json result;
+        parser(i.get(), cb, allow_exceptions, ignore_comments).parse(true, result);
+        return result;
+    }
+
+    /*!
+    @brief check if the input is valid JSON
 
-    This function reads from a compatible input. Examples are:
-    - an array of 1-byte values
-    - strings with character/literal type with size of 1 byte
-    - input streams
-    - container with contiguous storage of 1-byte values. Compatible container
-      types include `std::vector`, `std::string`, `std::array`,
-      `std::valarray`, and `std::initializer_list`. Furthermore, C-style
-      arrays can be used with `std::begin()`/`std::end()`. User-defined
-      containers can be used as long as they implement random-access iterators
-      and a contiguous storage.
-
-    @pre Each element of the container has a size of 1 byte. Violating this
-    precondition yields undefined behavior. **This precondition is enforced
-    with a static assertion.**
-
-    @pre The container storage is contiguous. Violating this precondition
-    yields undefined behavior. **This precondition is enforced with an
-    assertion.**
-    @pre Each element of the container has a size of 1 byte. Violating this
-    precondition yields undefined behavior. **This precondition is enforced
-    with a static assertion.**
-
-    @warning There is no way to enforce all preconditions at compile-time. If
-             the function is called with a noncompliant container and with
-             assertions switched off, the behavior is undefined and will most
-             likely yield segmentation violation.
+    Unlike the @ref parse(InputType&&, const parser_callback_t,const bool)
+    function, this function neither throws an exception in case of invalid JSON
+    input (i.e., a parse error) nor creates diagnostic information.
 
-    @param[in] i  input to read from
-    @param[in] cb  a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-    @param[in] allow_exceptions  whether to throw exceptions in case of a
-    parse error (optional, true by default)
+    @tparam InputType A compatible input, for instance
+    - an std::istream object
+    - a FILE pointer
+    - a C-style array of characters
+    - a pointer to a null-terminated string of single byte characters
+    - an object obj for which begin(obj) and end(obj) produces a valid pair of
+      iterators.
 
-    @return result of the deserialization
+    @param[in] i input to read from
+    @param[in] ignore_comments  whether comments should be ignored and treated
+    like whitespace (true) or yield a parse error (true); (optional, false by
+    default)
 
-    @throw parse_error.101 if a parse error occurs; example: `""unexpected end
-    of input; expected string literal""`
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
+    @return Whether the input read from @a i is valid JSON.
 
     @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
+    LL(1) parser.
 
     @note A UTF-8 byte order mark is silently ignored.
 
-    @liveexample{The example below demonstrates the `parse()` function reading
-    from an array.,parse__array__parser_callback_t}
-
-    @liveexample{The example below demonstrates the `parse()` function with
-    and without callback function.,parse__string__parser_callback_t}
-
-    @liveexample{The example below demonstrates the `parse()` function with
-    and without callback function.,parse__istream__parser_callback_t}
-
-    @liveexample{The example below demonstrates the `parse()` function reading
-    from a contiguous container.,parse__contiguouscontainer__parser_callback_t}
-
-    @since version 2.0.3 (contiguous containers)
+    @liveexample{The example below demonstrates the `accept()` function reading
+    from a string.,accept__string}
     */
-    static basic_json parse(detail::input_adapter&& i,
-                            const parser_callback_t cb = nullptr,
-                            const bool allow_exceptions = true)
+    template<typename InputType>
+    static bool accept(InputType&& i,
+                       const bool ignore_comments = false)
     {
-        basic_json result;
-        parser(i, cb, allow_exceptions).parse(true, result);
-        return result;
+        return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments).accept(true);
+    }
+
+    template<typename IteratorType>
+    static bool accept(IteratorType first, IteratorType last,
+                       const bool ignore_comments = false)
+    {
+        return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments).accept(true);
     }
 
-    static bool accept(detail::input_adapter&& i)
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, accept(ptr, ptr + len))
+    static bool accept(detail::span_input_adapter&& i,
+                       const bool ignore_comments = false)
     {
-        return parser(i).accept(true);
+        return parser(i.get(), nullptr, false, ignore_comments).accept(true);
     }
 
     /*!
@@ -18449,36 +24514,20 @@ class basic_json
     The SAX event lister must follow the interface of @ref json_sax.
 
     This function reads from a compatible input. Examples are:
-    - an array of 1-byte values
-    - strings with character/literal type with size of 1 byte
-    - input streams
-    - container with contiguous storage of 1-byte values. Compatible container
-      types include `std::vector`, `std::string`, `std::array`,
-      `std::valarray`, and `std::initializer_list`. Furthermore, C-style
-      arrays can be used with `std::begin()`/`std::end()`. User-defined
-      containers can be used as long as they implement random-access iterators
-      and a contiguous storage.
-
-    @pre Each element of the container has a size of 1 byte. Violating this
-    precondition yields undefined behavior. **This precondition is enforced
-    with a static assertion.**
-
-    @pre The container storage is contiguous. Violating this precondition
-    yields undefined behavior. **This precondition is enforced with an
-    assertion.**
-    @pre Each element of the container has a size of 1 byte. Violating this
-    precondition yields undefined behavior. **This precondition is enforced
-    with a static assertion.**
-
-    @warning There is no way to enforce all preconditions at compile-time. If
-             the function is called with a noncompliant container and with
-             assertions switched off, the behavior is undefined and will most
-             likely yield segmentation violation.
+    - an std::istream object
+    - a FILE pointer
+    - a C-style array of characters
+    - a pointer to a null-terminated string of single byte characters
+    - an object obj for which begin(obj) and end(obj) produces a valid pair of
+      iterators.
 
     @param[in] i  input to read from
     @param[in,out] sax  SAX event listener
     @param[in] format  the format to parse (JSON, CBOR, MessagePack, or UBJSON)
     @param[in] strict  whether the input has to be consumed completely
+    @param[in] ignore_comments  whether comments should be ignored and treated
+    like whitespace (true) or yield a parse error (true); (optional, false by
+    default); only applies to the JSON file format.
 
     @return return value of the last processed SAX event
 
@@ -18499,99 +24548,48 @@ class basic_json
 
     @since version 3.2.0
     */
-    template <typename SAX>
-    static bool sax_parse(detail::input_adapter&& i, SAX* sax,
+    template <typename InputType, typename SAX>
+    JSON_HEDLEY_NON_NULL(2)
+    static bool sax_parse(InputType&& i, SAX* sax,
                           input_format_t format = input_format_t::json,
-                          const bool strict = true)
-    {
-        assert(sax);
-        switch (format)
-        {
-            case input_format_t::json:
-                return parser(std::move(i)).sax_parse(sax, strict);
-            default:
-                return detail::binary_reader<basic_json, SAX>(std::move(i)).sax_parse(format, sax, strict);
-        }
-    }
-
-    /*!
-    @brief deserialize from an iterator range with contiguous storage
-
-    This function reads from an iterator range of a container with contiguous
-    storage of 1-byte values. Compatible container types include
-    `std::vector`, `std::string`, `std::array`, `std::valarray`, and
-    `std::initializer_list`. Furthermore, C-style arrays can be used with
-    `std::begin()`/`std::end()`. User-defined containers can be used as long
-    as they implement random-access iterators and a contiguous storage.
-
-    @pre The iterator range is contiguous. Violating this precondition yields
-    undefined behavior. **This precondition is enforced with an assertion.**
-    @pre Each element in the range has a size of 1 byte. Violating this
-    precondition yields undefined behavior. **This precondition is enforced
-    with a static assertion.**
-
-    @warning There is no way to enforce all preconditions at compile-time. If
-             the function is called with noncompliant iterators and with
-             assertions switched off, the behavior is undefined and will most
-             likely yield segmentation violation.
-
-    @tparam IteratorType iterator of container with contiguous storage
-    @param[in] first  begin of the range to parse (included)
-    @param[in] last  end of the range to parse (excluded)
-    @param[in] cb  a parser callback function of type @ref parser_callback_t
-    which is used to control the deserialization by filtering unwanted values
-    (optional)
-    @param[in] allow_exceptions  whether to throw exceptions in case of a
-    parse error (optional, true by default)
-
-    @return result of the deserialization
-
-    @throw parse_error.101 in case of an unexpected token
-    @throw parse_error.102 if to_unicode fails or surrogate error
-    @throw parse_error.103 if to_unicode fails
-
-    @complexity Linear in the length of the input. The parser is a predictive
-    LL(1) parser. The complexity can be higher if the parser callback function
-    @a cb has a super-linear complexity.
-
-    @note A UTF-8 byte order mark is silently ignored.
-
-    @liveexample{The example below demonstrates the `parse()` function reading
-    from an iterator range.,parse__iteratortype__parser_callback_t}
-
-    @since version 2.0.3
-    */
-    template<class IteratorType, typename std::enable_if<
-                 std::is_base_of<
-                     std::random_access_iterator_tag,
-                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
-    static basic_json parse(IteratorType first, IteratorType last,
-                            const parser_callback_t cb = nullptr,
-                            const bool allow_exceptions = true)
+                          const bool strict = true,
+                          const bool ignore_comments = false)
     {
-        basic_json result;
-        parser(detail::input_adapter(first, last), cb, allow_exceptions).parse(true, result);
-        return result;
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        return format == input_format_t::json
+               ? parser(std::move(ia), nullptr, true, ignore_comments).sax_parse(sax, strict)
+               : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia)).sax_parse(format, sax, strict);
     }
 
-    template<class IteratorType, typename std::enable_if<
-                 std::is_base_of<
-                     std::random_access_iterator_tag,
-                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
-    static bool accept(IteratorType first, IteratorType last)
+    template<class IteratorType, class SAX>
+    JSON_HEDLEY_NON_NULL(3)
+    static bool sax_parse(IteratorType first, IteratorType last, SAX* sax,
+                          input_format_t format = input_format_t::json,
+                          const bool strict = true,
+                          const bool ignore_comments = false)
     {
-        return parser(detail::input_adapter(first, last)).accept(true);
+        auto ia = detail::input_adapter(std::move(first), std::move(last));
+        return format == input_format_t::json
+               ? parser(std::move(ia), nullptr, true, ignore_comments).sax_parse(sax, strict)
+               : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia)).sax_parse(format, sax, strict);
     }
 
-    template<class IteratorType, class SAX, typename std::enable_if<
-                 std::is_base_of<
-                     std::random_access_iterator_tag,
-                     typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
-    static bool sax_parse(IteratorType first, IteratorType last, SAX* sax)
+    template <typename SAX>
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, sax_parse(ptr, ptr + len, ...))
+    JSON_HEDLEY_NON_NULL(2)
+    static bool sax_parse(detail::span_input_adapter&& i, SAX* sax,
+                          input_format_t format = input_format_t::json,
+                          const bool strict = true,
+                          const bool ignore_comments = false)
     {
-        return parser(detail::input_adapter(first, last)).sax_parse(sax);
+        auto ia = i.get();
+        return format == input_format_t::json
+               // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
+               ? parser(std::move(ia), nullptr, true, ignore_comments).sax_parse(sax, strict)
+               // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
+               : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia)).sax_parse(format, sax, strict);
     }
-
+#ifndef JSON_NO_IO
     /*!
     @brief deserialize from stream
     @deprecated This stream operator is deprecated and will be removed in
@@ -18600,7 +24598,7 @@ class basic_json
                 instead; that is, replace calls like `j << i;` with `i >> j;`.
     @since version 1.0.0; deprecated since version 3.0.0
     */
-    JSON_DEPRECATED
+    JSON_HEDLEY_DEPRECATED_FOR(3.0.0, operator>>(std::istream&, basic_json&))
     friend std::istream& operator<<(basic_json& j, std::istream& i)
     {
         return operator>>(i, j);
@@ -18636,7 +24634,7 @@ class basic_json
         parser(detail::input_adapter(i)).parse(false, j);
         return i;
     }
-
+#endif  // JSON_NO_IO
     /// @}
 
     ///////////////////////////
@@ -18658,6 +24656,7 @@ class basic_json
             number      | `"number"` (for all number types)
             object      | `"object"`
             array       | `"array"`
+            binary      | `"binary"`
             discarded   | `"discarded"`
 
     @exceptionsafety No-throw guarantee: this function never throws exceptions.
@@ -18667,12 +24666,13 @@ class basic_json
     @liveexample{The following code exemplifies `type_name()` for all JSON
     types.,type_name}
 
-    @sa @ref type() -- return the type of the JSON value
-    @sa @ref operator value_t() -- return the type of the JSON value (implicit)
+    @sa see @ref type() -- return the type of the JSON value
+    @sa see @ref operator value_t() -- return the type of the JSON value (implicit)
 
     @since version 1.0.0, public since 2.1.0, `const char*` and `noexcept`
     since 3.0.0
     */
+    JSON_HEDLEY_RETURNS_NON_NULL
     const char* type_name() const noexcept
     {
         {
@@ -18688,8 +24688,13 @@ class basic_json
                     return "string";
                 case value_t::boolean:
                     return "boolean";
+                case value_t::binary:
+                    return "binary";
                 case value_t::discarded:
                     return "discarded";
+                case value_t::number_integer:
+                case value_t::number_unsigned:
+                case value_t::number_float:
                 default:
                     return "number";
             }
@@ -18697,7 +24702,7 @@ class basic_json
     }
 
 
-  private:
+  JSON_PRIVATE_UNLESS_TESTED:
     //////////////////////
     // member variables //
     //////////////////////
@@ -18708,6 +24713,11 @@ class basic_json
     /// the value of the current element
     json_value m_value = {};
 
+#if JSON_DIAGNOSTICS
+    /// a pointer to a parent value (for debugging purposes)
+    basic_json* m_parent = nullptr;
+#endif
+
     //////////////////////////////////////////
     // binary serialization/deserialization //
     //////////////////////////////////////////
@@ -18747,7 +24757,8 @@ class basic_json
     number_unsigned | 256..65535                                 | Unsigned integer (2 bytes follow)  | 0x19
     number_unsigned | 65536..4294967295                          | Unsigned integer (4 bytes follow)  | 0x1A
     number_unsigned | 4294967296..18446744073709551615           | Unsigned integer (8 bytes follow)  | 0x1B
-    number_float    | *any value*                                | Double-Precision Float             | 0xFB
+    number_float    | *any value representable by a float*       | Single-Precision Float             | 0xFA
+    number_float    | *any value NOT representable by a float*   | Double-Precision Float             | 0xFB
     string          | *length*: 0..23                            | UTF-8 string                       | 0x60..0x77
     string          | *length*: 23..255                          | UTF-8 string (1 byte follow)       | 0x78
     string          | *length*: 256..65535                       | UTF-8 string (2 bytes follow)      | 0x79
@@ -18763,6 +24774,15 @@ class basic_json
     object          | *size*: 256..65535                         | map (2 bytes follow)               | 0xB9
     object          | *size*: 65536..4294967295                  | map (4 bytes follow)               | 0xBA
     object          | *size*: 4294967296..18446744073709551615   | map (8 bytes follow)               | 0xBB
+    binary          | *size*: 0..23                              | byte string                        | 0x40..0x57
+    binary          | *size*: 23..255                            | byte string (1 byte follow)        | 0x58
+    binary          | *size*: 256..65535                         | byte string (2 bytes follow)       | 0x59
+    binary          | *size*: 65536..4294967295                  | byte string (4 bytes follow)       | 0x5A
+    binary          | *size*: 4294967296..18446744073709551615   | byte string (8 bytes follow)       | 0x5B
+
+    Binary values with subtype are mapped to tagged values (0xD8..0xDB)
+    depending on the subtype, followed by a byte string, see "binary" cells
+    in the table above.
 
     @note The mapping is **complete** in the sense that any JSON value type
           can be converted to a CBOR value.
@@ -18772,23 +24792,22 @@ class basic_json
           function which serializes NaN or Infinity to `null`.
 
     @note The following CBOR types are not used in the conversion:
-          - byte strings (0x40..0x5F)
           - UTF-8 strings terminated by "break" (0x7F)
           - arrays terminated by "break" (0x9F)
           - maps terminated by "break" (0xBF)
+          - byte strings terminated by "break" (0x5F)
           - date/time (0xC0..0xC1)
           - bignum (0xC2..0xC3)
           - decimal fraction (0xC4)
           - bigfloat (0xC5)
-          - tagged items (0xC6..0xD4, 0xD8..0xDB)
           - expected conversions (0xD5..0xD7)
           - simple values (0xE0..0xF3, 0xF8)
           - undefined (0xF7)
-          - half and single-precision floats (0xF9-0xFA)
+          - half-precision floats (0xF9)
           - break (0xFF)
 
     @param[in] j  JSON value to serialize
-    @return MessagePack serialization as byte vector
+    @return CBOR serialization as byte vector
 
     @complexity Linear in the size of the JSON value @a j.
 
@@ -18796,24 +24815,25 @@ class basic_json
     vector in CBOR format.,to_cbor}
 
     @sa http://cbor.io
-    @sa @ref from_cbor(detail::input_adapter&&, const bool, const bool) for the
+    @sa see @ref from_cbor(InputType&&, const bool, const bool, const cbor_tag_handler_t) for the
         analogous deserialization
-    @sa @ref to_msgpack(const basic_json&) for the related MessagePack format
-    @sa @ref to_ubjson(const basic_json&, const bool, const bool) for the
+    @sa see @ref to_msgpack(const basic_json&) for the related MessagePack format
+    @sa see @ref to_ubjson(const basic_json&, const bool, const bool) for the
              related UBJSON format
 
-    @since version 2.0.9
+    @since version 2.0.9; compact representation of floating-point numbers
+           since version 3.8.0
     */
-    static std::vector<uint8_t> to_cbor(const basic_json& j)
+    static std::vector<std::uint8_t> to_cbor(const basic_json& j)
     {
-        std::vector<uint8_t> result;
+        std::vector<std::uint8_t> result;
         to_cbor(j, result);
         return result;
     }
 
-    static void to_cbor(const basic_json& j, detail::output_adapter<uint8_t> o)
+    static void to_cbor(const basic_json& j, detail::output_adapter<std::uint8_t> o)
     {
-        binary_writer<uint8_t>(o).write_cbor(j);
+        binary_writer<std::uint8_t>(o).write_cbor(j);
     }
 
     static void to_cbor(const basic_json& j, detail::output_adapter<char> o)
@@ -18851,7 +24871,8 @@ class basic_json
     number_unsigned | 256..65535                        | uint 16          | 0xCD
     number_unsigned | 65536..4294967295                 | uint 32          | 0xCE
     number_unsigned | 4294967296..18446744073709551615  | uint 64          | 0xCF
-    number_float    | *any value*                       | float 64         | 0xCB
+    number_float    | *any value representable by a float*     | float 32 | 0xCA
+    number_float    | *any value NOT representable by a float* | float 64 | 0xCB
     string          | *length*: 0..31                   | fixstr           | 0xA0..0xBF
     string          | *length*: 32..255                 | str 8            | 0xD9
     string          | *length*: 256..65535              | str 16           | 0xDA
@@ -18862,21 +24883,19 @@ class basic_json
     object          | *size*: 0..15                     | fix map          | 0x80..0x8F
     object          | *size*: 16..65535                 | map 16           | 0xDE
     object          | *size*: 65536..4294967295         | map 32           | 0xDF
+    binary          | *size*: 0..255                    | bin 8            | 0xC4
+    binary          | *size*: 256..65535                | bin 16           | 0xC5
+    binary          | *size*: 65536..4294967295         | bin 32           | 0xC6
 
     @note The mapping is **complete** in the sense that any JSON value type
           can be converted to a MessagePack value.
 
     @note The following values can **not** be converted to a MessagePack value:
           - strings with more than 4294967295 bytes
+          - byte strings with more than 4294967295 bytes
           - arrays with more than 4294967295 elements
           - objects with more than 4294967295 elements
 
-    @note The following MessagePack types are not used in the conversion:
-          - bin 8 - bin 32 (0xC4..0xC6)
-          - ext 8 - ext 32 (0xC7..0xC9)
-          - float 32 (0xCA)
-          - fixext 1 - fixext 16 (0xD4..0xD8)
-
     @note Any MessagePack output created @ref to_msgpack can be successfully
           parsed by @ref from_msgpack.
 
@@ -18893,23 +24912,23 @@ class basic_json
     vector in MessagePack format.,to_msgpack}
 
     @sa http://msgpack.org
-    @sa @ref from_msgpack for the analogous deserialization
-    @sa @ref to_cbor(const basic_json& for the related CBOR format
-    @sa @ref to_ubjson(const basic_json&, const bool, const bool) for the
+    @sa see @ref from_msgpack for the analogous deserialization
+    @sa see @ref to_cbor(const basic_json& for the related CBOR format
+    @sa see @ref to_ubjson(const basic_json&, const bool, const bool) for the
              related UBJSON format
 
     @since version 2.0.9
     */
-    static std::vector<uint8_t> to_msgpack(const basic_json& j)
+    static std::vector<std::uint8_t> to_msgpack(const basic_json& j)
     {
-        std::vector<uint8_t> result;
+        std::vector<std::uint8_t> result;
         to_msgpack(j, result);
         return result;
     }
 
-    static void to_msgpack(const basic_json& j, detail::output_adapter<uint8_t> o)
+    static void to_msgpack(const basic_json& j, detail::output_adapter<std::uint8_t> o)
     {
-        binary_writer<uint8_t>(o).write_msgpack(j);
+        binary_writer<std::uint8_t>(o).write_msgpack(j);
     }
 
     static void to_msgpack(const basic_json& j, detail::output_adapter<char> o)
@@ -18945,6 +24964,7 @@ class basic_json
     number_unsigned | 256..32767                        | int16       | `I`
     number_unsigned | 32768..2147483647                 | int32       | `l`
     number_unsigned | 2147483648..9223372036854775807   | int64       | `L`
+    number_unsigned | 2147483649..18446744073709551615  | high-precision | `H`
     number_float    | *any value*                       | float64     | `D`
     string          | *with shortest length indicator*  | string      | `S`
     array           | *see notes on optimized format*   | array       | `[`
@@ -18955,7 +24975,6 @@ class basic_json
 
     @note The following values can **not** be converted to a UBJSON value:
           - strings with more than 9223372036854775807 bytes (theoretical)
-          - unsigned integer numbers above 9223372036854775807
 
     @note The following markers are not used in the conversion:
           - `Z`: no-op values are not created.
@@ -18978,6 +24997,12 @@ class basic_json
           the benefit of this parameter is that the receiving side is
           immediately informed on the number of elements of the container.
 
+    @note If the JSON data contains the binary type, the value stored is a list
+          of integers, as suggested by the UBJSON documentation.  In particular,
+          this means that serialization and the deserialization of a JSON
+          containing binary values into UBJSON and back will result in a
+          different JSON object.
+
     @param[in] j  JSON value to serialize
     @param[in] use_size  whether to add size annotations to container types
     @param[in] use_type  whether to add type annotations to container types
@@ -18990,26 +25015,26 @@ class basic_json
     vector in UBJSON format.,to_ubjson}
 
     @sa http://ubjson.org
-    @sa @ref from_ubjson(detail::input_adapter&&, const bool, const bool) for the
+    @sa see @ref from_ubjson(InputType&&, const bool, const bool) for the
         analogous deserialization
-    @sa @ref to_cbor(const basic_json& for the related CBOR format
-    @sa @ref to_msgpack(const basic_json&) for the related MessagePack format
+    @sa see @ref to_cbor(const basic_json& for the related CBOR format
+    @sa see @ref to_msgpack(const basic_json&) for the related MessagePack format
 
     @since version 3.1.0
     */
-    static std::vector<uint8_t> to_ubjson(const basic_json& j,
-                                          const bool use_size = false,
-                                          const bool use_type = false)
+    static std::vector<std::uint8_t> to_ubjson(const basic_json& j,
+            const bool use_size = false,
+            const bool use_type = false)
     {
-        std::vector<uint8_t> result;
+        std::vector<std::uint8_t> result;
         to_ubjson(j, result, use_size, use_type);
         return result;
     }
 
-    static void to_ubjson(const basic_json& j, detail::output_adapter<uint8_t> o,
+    static void to_ubjson(const basic_json& j, detail::output_adapter<std::uint8_t> o,
                           const bool use_size = false, const bool use_type = false)
     {
-        binary_writer<uint8_t>(o).write_ubjson(j, use_size, use_type);
+        binary_writer<std::uint8_t>(o).write_ubjson(j, use_size, use_type);
     }
 
     static void to_ubjson(const basic_json& j, detail::output_adapter<char> o,
@@ -19042,6 +25067,7 @@ class basic_json
     string          | *any value*                       | string      | 0x02
     array           | *any value*                       | document    | 0x04
     object          | *any value*                       | document    | 0x03
+    binary          | *any value*                       | binary      | 0x05
 
     @warning The mapping is **incomplete**, since only JSON-objects (and things
     contained therein) can be serialized to BSON.
@@ -19067,16 +25093,16 @@ class basic_json
     vector in BSON format.,to_bson}
 
     @sa http://bsonspec.org/spec.html
-    @sa @ref from_bson(detail::input_adapter&&, const bool strict) for the
+    @sa see @ref from_bson(detail::input_adapter&&, const bool strict) for the
         analogous deserialization
-    @sa @ref to_ubjson(const basic_json&, const bool, const bool) for the
+    @sa see @ref to_ubjson(const basic_json&, const bool, const bool) for the
              related UBJSON format
-    @sa @ref to_cbor(const basic_json&) for the related CBOR format
-    @sa @ref to_msgpack(const basic_json&) for the related MessagePack format
+    @sa see @ref to_cbor(const basic_json&) for the related CBOR format
+    @sa see @ref to_msgpack(const basic_json&) for the related MessagePack format
     */
-    static std::vector<uint8_t> to_bson(const basic_json& j)
+    static std::vector<std::uint8_t> to_bson(const basic_json& j)
     {
-        std::vector<uint8_t> result;
+        std::vector<std::uint8_t> result;
         to_bson(j, result);
         return result;
     }
@@ -19087,15 +25113,15 @@ class basic_json
     @param j The JSON object to convert to BSON.
     @param o The output adapter that receives the binary BSON representation.
     @pre The input `j` shall be an object: `j.is_object() == true`
-    @sa @ref to_bson(const basic_json&)
+    @sa see @ref to_bson(const basic_json&)
     */
-    static void to_bson(const basic_json& j, detail::output_adapter<uint8_t> o)
+    static void to_bson(const basic_json& j, detail::output_adapter<std::uint8_t> o)
     {
-        binary_writer<uint8_t>(o).write_bson(j);
+        binary_writer<std::uint8_t>(o).write_bson(j);
     }
 
     /*!
-    @copydoc to_bson(const basic_json&, detail::output_adapter<uint8_t>)
+    @copydoc to_bson(const basic_json&, detail::output_adapter<std::uint8_t>)
     */
     static void to_bson(const basic_json& j, detail::output_adapter<char> o)
     {
@@ -19123,7 +25149,11 @@ class basic_json
     Negative integer       | number_integer  | 0x39
     Negative integer       | number_integer  | 0x3A
     Negative integer       | number_integer  | 0x3B
-    Negative integer       | number_integer  | 0x40..0x57
+    Byte string            | binary          | 0x40..0x57
+    Byte string            | binary          | 0x58
+    Byte string            | binary          | 0x59
+    Byte string            | binary          | 0x5A
+    Byte string            | binary          | 0x5B
     UTF-8 string           | string          | 0x60..0x77
     UTF-8 string           | string          | 0x78
     UTF-8 string           | string          | 0x79
@@ -19152,12 +25182,10 @@ class basic_json
     @warning The mapping is **incomplete** in the sense that not all CBOR
              types can be converted to a JSON value. The following CBOR types
              are not supported and will yield parse errors (parse_error.112):
-             - byte strings (0x40..0x5F)
              - date/time (0xC0..0xC1)
              - bignum (0xC2..0xC3)
              - decimal fraction (0xC4)
              - bigfloat (0xC5)
-             - tagged items (0xC6..0xD4, 0xD8..0xDB)
              - expected conversions (0xD5..0xD7)
              - simple values (0xE0..0xF3, 0xF8)
              - undefined (0xF7)
@@ -19174,8 +25202,11 @@ class basic_json
                        (true by default)
     @param[in] allow_exceptions  whether to throw exceptions in case of a
     parse error (optional, true by default)
+    @param[in] tag_handler how to treat CBOR tags (optional, error by default)
 
-    @return deserialized JSON value
+    @return deserialized JSON value; in case of a parse error and
+            @a allow_exceptions set to `false`, the return value will be
+            value_t::discarded.
 
     @throw parse_error.110 if the given input ends prematurely or the end of
     file was not reached when @a strict was set to true
@@ -19189,39 +25220,72 @@ class basic_json
     format to a JSON value.,from_cbor}
 
     @sa http://cbor.io
-    @sa @ref to_cbor(const basic_json&) for the analogous serialization
-    @sa @ref from_msgpack(detail::input_adapter&&, const bool, const bool) for the
+    @sa see @ref to_cbor(const basic_json&) for the analogous serialization
+    @sa see @ref from_msgpack(InputType&&, const bool, const bool) for the
         related MessagePack format
-    @sa @ref from_ubjson(detail::input_adapter&&, const bool, const bool) for the
+    @sa see @ref from_ubjson(InputType&&, const bool, const bool) for the
         related UBJSON format
 
     @since version 2.0.9; parameter @a start_index since 2.1.1; changed to
            consume input adapters, removed start_index parameter, and added
            @a strict parameter since 3.0.0; added @a allow_exceptions parameter
-           since 3.2.0
+           since 3.2.0; added @a tag_handler parameter since 3.9.0.
     */
-    static basic_json from_cbor(detail::input_adapter&& i,
+    template<typename InputType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json from_cbor(InputType&& i,
                                 const bool strict = true,
-                                const bool allow_exceptions = true)
+                                const bool allow_exceptions = true,
+                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(i)).sax_parse(input_format_t::cbor, &sdp, strict);
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler);
         return res ? result : basic_json(value_t::discarded);
     }
 
     /*!
-    @copydoc from_cbor(detail::input_adapter&&, const bool, const bool)
+    @copydoc from_cbor(InputType&&, const bool, const bool, const cbor_tag_handler_t)
     */
-    template<typename A1, typename A2,
-             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
-    static basic_json from_cbor(A1 && a1, A2 && a2,
+    template<typename IteratorType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json from_cbor(IteratorType first, IteratorType last,
                                 const bool strict = true,
-                                const bool allow_exceptions = true)
+                                const bool allow_exceptions = true,
+                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
+    {
+        basic_json result;
+        detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
+        auto ia = detail::input_adapter(std::move(first), std::move(last));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler);
+        return res ? result : basic_json(value_t::discarded);
+    }
+
+    template<typename T>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_cbor(ptr, ptr + len))
+    static basic_json from_cbor(const T* ptr, std::size_t len,
+                                const bool strict = true,
+                                const bool allow_exceptions = true,
+                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
+    {
+        return from_cbor(ptr, ptr + len, strict, allow_exceptions, tag_handler);
+    }
+
+
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_cbor(ptr, ptr + len))
+    static basic_json from_cbor(detail::span_input_adapter&& i,
+                                const bool strict = true,
+                                const bool allow_exceptions = true,
+                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).sax_parse(input_format_t::cbor, &sdp, strict);
+        auto ia = i.get();
+        // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -19259,15 +25323,19 @@ class basic_json
     array 32         | array           | 0xDD
     map 16           | object          | 0xDE
     map 32           | object          | 0xDF
+    bin 8            | binary          | 0xC4
+    bin 16           | binary          | 0xC5
+    bin 32           | binary          | 0xC6
+    ext 8            | binary          | 0xC7
+    ext 16           | binary          | 0xC8
+    ext 32           | binary          | 0xC9
+    fixext 1         | binary          | 0xD4
+    fixext 2         | binary          | 0xD5
+    fixext 4         | binary          | 0xD6
+    fixext 8         | binary          | 0xD7
+    fixext 16        | binary          | 0xD8
     negative fixint  | number_integer  | 0xE0-0xFF
 
-    @warning The mapping is **incomplete** in the sense that not all
-             MessagePack types can be converted to a JSON value. The following
-             MessagePack types are not supported and will yield parse errors:
-              - bin 8 - bin 32 (0xC4..0xC6)
-              - ext 8 - ext 32 (0xC7..0xC9)
-              - fixext 1 - fixext 16 (0xD4..0xD8)
-
     @note Any MessagePack output created @ref to_msgpack can be successfully
           parsed by @ref from_msgpack.
 
@@ -19278,7 +25346,9 @@ class basic_json
     @param[in] allow_exceptions  whether to throw exceptions in case of a
     parse error (optional, true by default)
 
-    @return deserialized JSON value
+    @return deserialized JSON value; in case of a parse error and
+            @a allow_exceptions set to `false`, the return value will be
+            value_t::discarded.
 
     @throw parse_error.110 if the given input ends prematurely or the end of
     file was not reached when @a strict was set to true
@@ -19292,12 +25362,12 @@ class basic_json
     MessagePack format to a JSON value.,from_msgpack}
 
     @sa http://msgpack.org
-    @sa @ref to_msgpack(const basic_json&) for the analogous serialization
-    @sa @ref from_cbor(detail::input_adapter&&, const bool, const bool) for the
+    @sa see @ref to_msgpack(const basic_json&) for the analogous serialization
+    @sa see @ref from_cbor(InputType&&, const bool, const bool, const cbor_tag_handler_t) for the
         related CBOR format
-    @sa @ref from_ubjson(detail::input_adapter&&, const bool, const bool) for
+    @sa see @ref from_ubjson(InputType&&, const bool, const bool) for
         the related UBJSON format
-    @sa @ref from_bson(detail::input_adapter&&, const bool, const bool) for
+    @sa see @ref from_bson(InputType&&, const bool, const bool) for
         the related BSON format
 
     @since version 2.0.9; parameter @a start_index since 2.1.1; changed to
@@ -19305,31 +25375,61 @@ class basic_json
            @a strict parameter since 3.0.0; added @a allow_exceptions parameter
            since 3.2.0
     */
-    static basic_json from_msgpack(detail::input_adapter&& i,
+    template<typename InputType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json from_msgpack(InputType&& i,
                                    const bool strict = true,
                                    const bool allow_exceptions = true)
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(i)).sax_parse(input_format_t::msgpack, &sdp, strict);
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::msgpack, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
     /*!
-    @copydoc from_msgpack(detail::input_adapter&&, const bool, const bool)
+    @copydoc from_msgpack(InputType&&, const bool, const bool)
     */
-    template<typename A1, typename A2,
-             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
-    static basic_json from_msgpack(A1 && a1, A2 && a2,
+    template<typename IteratorType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json from_msgpack(IteratorType first, IteratorType last,
+                                   const bool strict = true,
+                                   const bool allow_exceptions = true)
+    {
+        basic_json result;
+        detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
+        auto ia = detail::input_adapter(std::move(first), std::move(last));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::msgpack, &sdp, strict);
+        return res ? result : basic_json(value_t::discarded);
+    }
+
+
+    template<typename T>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_msgpack(ptr, ptr + len))
+    static basic_json from_msgpack(const T* ptr, std::size_t len,
+                                   const bool strict = true,
+                                   const bool allow_exceptions = true)
+    {
+        return from_msgpack(ptr, ptr + len, strict, allow_exceptions);
+    }
+
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_msgpack(ptr, ptr + len))
+    static basic_json from_msgpack(detail::span_input_adapter&& i,
                                    const bool strict = true,
                                    const bool allow_exceptions = true)
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).sax_parse(input_format_t::msgpack, &sdp, strict);
+        auto ia = i.get();
+        // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::msgpack, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
+
     /*!
     @brief create a JSON value from an input in UBJSON format
 
@@ -19351,6 +25451,7 @@ class basic_json
     int16       | number_integer                          | `I`
     int32       | number_integer                          | `l`
     int64       | number_integer                          | `L`
+    high-precision number | number_integer, number_unsigned, or number_float - depends on number string | 'H'
     string      | string                                  | `S`
     char        | string                                  | `C`
     array       | array (optimized values are supported)  | `[`
@@ -19365,7 +25466,9 @@ class basic_json
     @param[in] allow_exceptions  whether to throw exceptions in case of a
     parse error (optional, true by default)
 
-    @return deserialized JSON value
+    @return deserialized JSON value; in case of a parse error and
+            @a allow_exceptions set to `false`, the return value will be
+            value_t::discarded.
 
     @throw parse_error.110 if the given input ends prematurely or the end of
     file was not reached when @a strict was set to true
@@ -19378,42 +25481,71 @@ class basic_json
     UBJSON format to a JSON value.,from_ubjson}
 
     @sa http://ubjson.org
-    @sa @ref to_ubjson(const basic_json&, const bool, const bool) for the
+    @sa see @ref to_ubjson(const basic_json&, const bool, const bool) for the
              analogous serialization
-    @sa @ref from_cbor(detail::input_adapter&&, const bool, const bool) for the
+    @sa see @ref from_cbor(InputType&&, const bool, const bool, const cbor_tag_handler_t) for the
         related CBOR format
-    @sa @ref from_msgpack(detail::input_adapter&&, const bool, const bool) for
+    @sa see @ref from_msgpack(InputType&&, const bool, const bool) for
         the related MessagePack format
-    @sa @ref from_bson(detail::input_adapter&&, const bool, const bool) for
+    @sa see @ref from_bson(InputType&&, const bool, const bool) for
         the related BSON format
 
     @since version 3.1.0; added @a allow_exceptions parameter since 3.2.0
     */
-    static basic_json from_ubjson(detail::input_adapter&& i,
+    template<typename InputType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json from_ubjson(InputType&& i,
                                   const bool strict = true,
                                   const bool allow_exceptions = true)
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(i)).sax_parse(input_format_t::ubjson, &sdp, strict);
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::ubjson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
     /*!
-    @copydoc from_ubjson(detail::input_adapter&&, const bool, const bool)
+    @copydoc from_ubjson(InputType&&, const bool, const bool)
     */
-    template<typename A1, typename A2,
-             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
-    static basic_json from_ubjson(A1 && a1, A2 && a2,
+    template<typename IteratorType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json from_ubjson(IteratorType first, IteratorType last,
+                                  const bool strict = true,
+                                  const bool allow_exceptions = true)
+    {
+        basic_json result;
+        detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
+        auto ia = detail::input_adapter(std::move(first), std::move(last));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::ubjson, &sdp, strict);
+        return res ? result : basic_json(value_t::discarded);
+    }
+
+    template<typename T>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_ubjson(ptr, ptr + len))
+    static basic_json from_ubjson(const T* ptr, std::size_t len,
+                                  const bool strict = true,
+                                  const bool allow_exceptions = true)
+    {
+        return from_ubjson(ptr, ptr + len, strict, allow_exceptions);
+    }
+
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_ubjson(ptr, ptr + len))
+    static basic_json from_ubjson(detail::span_input_adapter&& i,
                                   const bool strict = true,
                                   const bool allow_exceptions = true)
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).sax_parse(input_format_t::ubjson, &sdp, strict);
+        auto ia = i.get();
+        // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::ubjson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
+
     /*!
     @brief Create a JSON value from an input in BSON format
 
@@ -19428,7 +25560,7 @@ class basic_json
     string          | 0x02             | string
     document        | 0x03             | object
     array           | 0x04             | array
-    binary          | 0x05             | still unsupported
+    binary          | 0x05             | binary
     undefined       | 0x06             | still unsupported
     ObjectId        | 0x07             | still unsupported
     boolean         | 0x08             | boolean
@@ -19454,7 +25586,9 @@ class basic_json
     @param[in] allow_exceptions  whether to throw exceptions in case of a
     parse error (optional, true by default)
 
-    @return deserialized JSON value
+    @return deserialized JSON value; in case of a parse error and
+            @a allow_exceptions set to `false`, the return value will be
+            value_t::discarded.
 
     @throw parse_error.114 if an unsupported BSON record type is encountered
 
@@ -19464,41 +25598,66 @@ class basic_json
     BSON format to a JSON value.,from_bson}
 
     @sa http://bsonspec.org/spec.html
-    @sa @ref to_bson(const basic_json&) for the analogous serialization
-    @sa @ref from_cbor(detail::input_adapter&&, const bool, const bool) for the
+    @sa see @ref to_bson(const basic_json&) for the analogous serialization
+    @sa see @ref from_cbor(InputType&&, const bool, const bool, const cbor_tag_handler_t) for the
         related CBOR format
-    @sa @ref from_msgpack(detail::input_adapter&&, const bool, const bool) for
+    @sa see @ref from_msgpack(InputType&&, const bool, const bool) for
         the related MessagePack format
-    @sa @ref from_ubjson(detail::input_adapter&&, const bool, const bool) for the
+    @sa see @ref from_ubjson(InputType&&, const bool, const bool) for the
         related UBJSON format
     */
-    static basic_json from_bson(detail::input_adapter&& i,
+    template<typename InputType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json from_bson(InputType&& i,
                                 const bool strict = true,
                                 const bool allow_exceptions = true)
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(i)).sax_parse(input_format_t::bson, &sdp, strict);
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::bson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
     /*!
-    @copydoc from_bson(detail::input_adapter&&, const bool, const bool)
+    @copydoc from_bson(InputType&&, const bool, const bool)
     */
-    template<typename A1, typename A2,
-             detail::enable_if_t<std::is_constructible<detail::input_adapter, A1, A2>::value, int> = 0>
-    static basic_json from_bson(A1 && a1, A2 && a2,
+    template<typename IteratorType>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    static basic_json from_bson(IteratorType first, IteratorType last,
                                 const bool strict = true,
                                 const bool allow_exceptions = true)
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(std::forward<A1>(a1), std::forward<A2>(a2))).sax_parse(input_format_t::bson, &sdp, strict);
+        auto ia = detail::input_adapter(std::move(first), std::move(last));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::bson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
+    template<typename T>
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_bson(ptr, ptr + len))
+    static basic_json from_bson(const T* ptr, std::size_t len,
+                                const bool strict = true,
+                                const bool allow_exceptions = true)
+    {
+        return from_bson(ptr, ptr + len, strict, allow_exceptions);
+    }
 
-
+    JSON_HEDLEY_WARN_UNUSED_RESULT
+    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_bson(ptr, ptr + len))
+    static basic_json from_bson(detail::span_input_adapter&& i,
+                                const bool strict = true,
+                                const bool allow_exceptions = true)
+    {
+        basic_json result;
+        detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
+        auto ia = i.get();
+        // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::bson, &sdp, strict);
+        return res ? result : basic_json(value_t::discarded);
+    }
     /// @}
 
     //////////////////////////
@@ -19551,7 +25710,7 @@ class basic_json
 
     Uses a JSON pointer to retrieve a reference to the respective JSON value.
     No bound checking is performed. The function does not change the JSON
-    value; no `null` values are created. In particular, the the special value
+    value; no `null` values are created. In particular, the special value
     `-` yields an exception.
 
     @param[in] ptr  JSON pointer to the desired element
@@ -19678,7 +25837,7 @@ class basic_json
     @liveexample{The following code shows how a JSON object is flattened to an
     object whose keys consist of JSON pointers.,flatten}
 
-    @sa @ref unflatten() for the reverse function
+    @sa see @ref unflatten() for the reverse function
 
     @since version 2.0.0
     */
@@ -19715,7 +25874,7 @@ class basic_json
     @liveexample{The following code shows how a flattened JSON object is
     unflattened into the original nested JSON object.,unflatten}
 
-    @sa @ref flatten() for the reverse function
+    @sa see @ref flatten() for the reverse function
 
     @since version 2.0.0
     */
@@ -19773,7 +25932,7 @@ class basic_json
     @liveexample{The following code shows how a JSON patch is applied to a
     value.,patch}
 
-    @sa @ref diff -- create a JSON patch by comparing two JSON values
+    @sa see @ref diff -- create a JSON patch by comparing two JSON values
 
     @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
     @sa [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
@@ -19822,71 +25981,75 @@ class basic_json
         const auto operation_add = [&result](json_pointer & ptr, basic_json val)
         {
             // adding to the root of the target document means replacing it
-            if (ptr.is_root())
+            if (ptr.empty())
             {
                 result = val;
+                return;
             }
-            else
+
+            // make sure the top element of the pointer exists
+            json_pointer top_pointer = ptr.top();
+            if (top_pointer != ptr)
+            {
+                result.at(top_pointer);
+            }
+
+            // get reference to parent of JSON pointer ptr
+            const auto last_path = ptr.back();
+            ptr.pop_back();
+            basic_json& parent = result[ptr];
+
+            switch (parent.m_type)
             {
-                // make sure the top element of the pointer exists
-                json_pointer top_pointer = ptr.top();
-                if (top_pointer != ptr)
+                case value_t::null:
+                case value_t::object:
                 {
-                    result.at(top_pointer);
+                    // use operator[] to add value
+                    parent[last_path] = val;
+                    break;
                 }
 
-                // get reference to parent of JSON pointer ptr
-                const auto last_path = ptr.pop_back();
-                basic_json& parent = result[ptr];
-
-                switch (parent.m_type)
+                case value_t::array:
                 {
-                    case value_t::null:
-                    case value_t::object:
+                    if (last_path == "-")
                     {
-                        // use operator[] to add value
-                        parent[last_path] = val;
-                        break;
+                        // special case: append to back
+                        parent.push_back(val);
                     }
-
-                    case value_t::array:
+                    else
                     {
-                        if (last_path == "-")
-                        {
-                            // special case: append to back
-                            parent.push_back(val);
-                        }
-                        else
+                        const auto idx = json_pointer::array_index(last_path);
+                        if (JSON_HEDLEY_UNLIKELY(idx > parent.size()))
                         {
-                            const auto idx = json_pointer::array_index(last_path);
-                            if (JSON_UNLIKELY(static_cast<size_type>(idx) > parent.size()))
-                            {
-                                // avoid undefined behavior
-                                JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range"));
-                            }
-
-                            // default case: insert add offset
-                            parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
+                            // avoid undefined behavior
+                            JSON_THROW(out_of_range::create(401, "array index " + std::to_string(idx) + " is out of range", parent));
                         }
-                        break;
-                    }
 
-                    // LCOV_EXCL_START
-                    default:
-                    {
-                        // if there exists a parent it cannot be primitive
-                        assert(false);
+                        // default case: insert add offset
+                        parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
                     }
-                        // LCOV_EXCL_STOP
+                    break;
                 }
+
+                // if there exists a parent it cannot be primitive
+                case value_t::string: // LCOV_EXCL_LINE
+                case value_t::boolean: // LCOV_EXCL_LINE
+                case value_t::number_integer: // LCOV_EXCL_LINE
+                case value_t::number_unsigned: // LCOV_EXCL_LINE
+                case value_t::number_float: // LCOV_EXCL_LINE
+                case value_t::binary: // LCOV_EXCL_LINE
+                case value_t::discarded: // LCOV_EXCL_LINE
+                default:            // LCOV_EXCL_LINE
+                    JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
             }
         };
 
         // wrapper for "remove" operation; remove value at ptr
-        const auto operation_remove = [&result](json_pointer & ptr)
+        const auto operation_remove = [this, &result](json_pointer & ptr)
         {
             // get reference to parent of JSON pointer ptr
-            const auto last_path = ptr.pop_back();
+            const auto last_path = ptr.back();
+            ptr.pop_back();
             basic_json& parent = result.at(ptr);
 
             // remove child
@@ -19894,26 +26057,26 @@ class basic_json
             {
                 // perform range check
                 auto it = parent.find(last_path);
-                if (JSON_LIKELY(it != parent.end()))
+                if (JSON_HEDLEY_LIKELY(it != parent.end()))
                 {
                     parent.erase(it);
                 }
                 else
                 {
-                    JSON_THROW(out_of_range::create(403, "key '" + last_path + "' not found"));
+                    JSON_THROW(out_of_range::create(403, "key '" + last_path + "' not found", *this));
                 }
             }
             else if (parent.is_array())
             {
                 // note erase performs range check
-                parent.erase(static_cast<size_type>(json_pointer::array_index(last_path)));
+                parent.erase(json_pointer::array_index(last_path));
             }
         };
 
         // type check: top level value must be an array
-        if (JSON_UNLIKELY(not json_patch.is_array()))
+        if (JSON_HEDLEY_UNLIKELY(!json_patch.is_array()))
         {
-            JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects"));
+            JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects", json_patch));
         }
 
         // iterate and apply the operations
@@ -19931,15 +26094,17 @@ class basic_json
                 const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";
 
                 // check if desired value is present
-                if (JSON_UNLIKELY(it == val.m_value.object->end()))
+                if (JSON_HEDLEY_UNLIKELY(it == val.m_value.object->end()))
                 {
-                    JSON_THROW(parse_error::create(105, 0, error_msg + " must have member '" + member + "'"));
+                    // NOLINTNEXTLINE(performance-inefficient-string-concatenation)
+                    JSON_THROW(parse_error::create(105, 0, error_msg + " must have member '" + member + "'", val));
                 }
 
                 // check if result is of type string
-                if (JSON_UNLIKELY(string_type and not it->second.is_string()))
+                if (JSON_HEDLEY_UNLIKELY(string_type && !it->second.is_string()))
                 {
-                    JSON_THROW(parse_error::create(105, 0, error_msg + " must have string member '" + member + "'"));
+                    // NOLINTNEXTLINE(performance-inefficient-string-concatenation)
+                    JSON_THROW(parse_error::create(105, 0, error_msg + " must have string member '" + member + "'", val));
                 }
 
                 // no error: return value
@@ -19947,14 +26112,14 @@ class basic_json
             };
 
             // type check: every element of the array must be an object
-            if (JSON_UNLIKELY(not val.is_object()))
+            if (JSON_HEDLEY_UNLIKELY(!val.is_object()))
             {
-                JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects"));
+                JSON_THROW(parse_error::create(104, 0, "JSON patch must be an array of objects", val));
             }
 
             // collect mandatory members
-            const std::string op = get_value("op", "op", true);
-            const std::string path = get_value(op, "path", true);
+            const auto op = get_value("op", "op", true).template get<std::string>();
+            const auto path = get_value(op, "path", true).template get<std::string>();
             json_pointer ptr(path);
 
             switch (get_op(op))
@@ -19980,7 +26145,7 @@ class basic_json
 
                 case patch_operations::move:
                 {
-                    const std::string from_path = get_value("move", "from", true);
+                    const auto from_path = get_value("move", "from", true).template get<std::string>();
                     json_pointer from_ptr(from_path);
 
                     // the "from" location must exist - use at()
@@ -19997,7 +26162,7 @@ class basic_json
 
                 case patch_operations::copy:
                 {
-                    const std::string from_path = get_value("copy", "from", true);
+                    const auto from_path = get_value("copy", "from", true).template get<std::string>();
                     const json_pointer from_ptr(from_path);
 
                     // the "from" location must exist - use at()
@@ -20025,19 +26190,20 @@ class basic_json
                     }
 
                     // throw an exception if test fails
-                    if (JSON_UNLIKELY(not success))
+                    if (JSON_HEDLEY_UNLIKELY(!success))
                     {
-                        JSON_THROW(other_error::create(501, "unsuccessful: " + val.dump()));
+                        JSON_THROW(other_error::create(501, "unsuccessful: " + val.dump(), val));
                     }
 
                     break;
                 }
 
                 case patch_operations::invalid:
+                default:
                 {
                     // op must be "add", "remove", "replace", "move", "copy", or
                     // "test"
-                    JSON_THROW(parse_error::create(105, 0, "operation value '" + op + "' is invalid"));
+                    JSON_THROW(parse_error::create(105, 0, "operation value '" + op + "' is invalid", val));
                 }
             }
         }
@@ -20071,13 +26237,14 @@ class basic_json
     @liveexample{The following code shows how a JSON patch is created as a
     diff for two JSON values.,diff}
 
-    @sa @ref patch -- apply a JSON patch
-    @sa @ref merge_patch -- apply a JSON Merge Patch
+    @sa see @ref patch -- apply a JSON patch
+    @sa see @ref merge_patch -- apply a JSON Merge Patch
 
     @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
 
     @since version 2.0.0
     */
+    JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json diff(const basic_json& source, const basic_json& target,
                            const std::string& path = "")
     {
@@ -20097,106 +26264,113 @@ class basic_json
             {
                 {"op", "replace"}, {"path", path}, {"value", target}
             });
+            return result;
         }
-        else
+
+        switch (source.type())
         {
-            switch (source.type())
+            case value_t::array:
             {
-                case value_t::array:
+                // first pass: traverse common elements
+                std::size_t i = 0;
+                while (i < source.size() && i < target.size())
                 {
-                    // first pass: traverse common elements
-                    std::size_t i = 0;
-                    while (i < source.size() and i < target.size())
-                    {
-                        // recursive call to compare array values at index i
-                        auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
-                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
-                        ++i;
-                    }
+                    // recursive call to compare array values at index i
+                    auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
+                    result.insert(result.end(), temp_diff.begin(), temp_diff.end());
+                    ++i;
+                }
 
-                    // i now reached the end of at least one array
-                    // in a second pass, traverse the remaining elements
+                // i now reached the end of at least one array
+                // in a second pass, traverse the remaining elements
 
-                    // remove my remaining elements
-                    const auto end_index = static_cast<difference_type>(result.size());
-                    while (i < source.size())
+                // remove my remaining elements
+                const auto end_index = static_cast<difference_type>(result.size());
+                while (i < source.size())
+                {
+                    // add operations in reverse order to avoid invalid
+                    // indices
+                    result.insert(result.begin() + end_index, object(
                     {
-                        // add operations in reverse order to avoid invalid
-                        // indices
-                        result.insert(result.begin() + end_index, object(
-                        {
-                            {"op", "remove"},
-                            {"path", path + "/" + std::to_string(i)}
-                        }));
-                        ++i;
-                    }
+                        {"op", "remove"},
+                        {"path", path + "/" + std::to_string(i)}
+                    }));
+                    ++i;
+                }
 
-                    // add other remaining elements
-                    while (i < target.size())
+                // add other remaining elements
+                while (i < target.size())
+                {
+                    result.push_back(
                     {
-                        result.push_back(
-                        {
-                            {"op", "add"},
-                            {"path", path + "/" + std::to_string(i)},
-                            {"value", target[i]}
-                        });
-                        ++i;
-                    }
-
-                    break;
+                        {"op", "add"},
+                        {"path", path + "/-"},
+                        {"value", target[i]}
+                    });
+                    ++i;
                 }
 
-                case value_t::object:
+                break;
+            }
+
+            case value_t::object:
+            {
+                // first pass: traverse this object's elements
+                for (auto it = source.cbegin(); it != source.cend(); ++it)
                 {
-                    // first pass: traverse this object's elements
-                    for (auto it = source.cbegin(); it != source.cend(); ++it)
-                    {
-                        // escape the key name to be used in a JSON patch
-                        const auto key = json_pointer::escape(it.key());
+                    // escape the key name to be used in a JSON patch
+                    const auto path_key = path + "/" + detail::escape(it.key());
 
-                        if (target.find(it.key()) != target.end())
-                        {
-                            // recursive call to compare object values at key it
-                            auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key);
-                            result.insert(result.end(), temp_diff.begin(), temp_diff.end());
-                        }
-                        else
-                        {
-                            // found a key that is not in o -> remove it
-                            result.push_back(object(
-                            {
-                                {"op", "remove"}, {"path", path + "/" + key}
-                            }));
-                        }
+                    if (target.find(it.key()) != target.end())
+                    {
+                        // recursive call to compare object values at key it
+                        auto temp_diff = diff(it.value(), target[it.key()], path_key);
+                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
                     }
-
-                    // second pass: traverse other object's elements
-                    for (auto it = target.cbegin(); it != target.cend(); ++it)
+                    else
                     {
-                        if (source.find(it.key()) == source.end())
+                        // found a key that is not in o -> remove it
+                        result.push_back(object(
                         {
-                            // found a key that is not in this -> add it
-                            const auto key = json_pointer::escape(it.key());
-                            result.push_back(
-                            {
-                                {"op", "add"}, {"path", path + "/" + key},
-                                {"value", it.value()}
-                            });
-                        }
+                            {"op", "remove"}, {"path", path_key}
+                        }));
                     }
-
-                    break;
                 }
 
-                default:
+                // second pass: traverse other object's elements
+                for (auto it = target.cbegin(); it != target.cend(); ++it)
                 {
-                    // both primitive type: replace value
-                    result.push_back(
+                    if (source.find(it.key()) == source.end())
                     {
-                        {"op", "replace"}, {"path", path}, {"value", target}
-                    });
-                    break;
+                        // found a key that is not in this -> add it
+                        const auto path_key = path + "/" + detail::escape(it.key());
+                        result.push_back(
+                        {
+                            {"op", "add"}, {"path", path_key},
+                            {"value", it.value()}
+                        });
+                    }
                 }
+
+                break;
+            }
+
+            case value_t::null:
+            case value_t::string:
+            case value_t::boolean:
+            case value_t::number_integer:
+            case value_t::number_unsigned:
+            case value_t::number_float:
+            case value_t::binary:
+            case value_t::discarded:
+            default:
+            {
+                // both primitive type: replace value
+                result.push_back(
+                {
+                    {"op", "replace"}, {"path", path}, {"value", target}
+                });
+                break;
             }
         }
 
@@ -20249,7 +26423,7 @@ class basic_json
     @liveexample{The following code shows how a JSON Merge Patch is applied to
     a JSON document.,merge_patch}
 
-    @sa @ref patch -- apply a JSON patch
+    @sa see @ref patch -- apply a JSON patch
     @sa [RFC 7396 (JSON Merge Patch)](https://tools.ietf.org/html/rfc7396)
 
     @since version 3.0.0
@@ -20258,7 +26432,7 @@ class basic_json
     {
         if (apply_patch.is_object())
         {
-            if (not is_object())
+            if (!is_object())
             {
                 *this = object();
             }
@@ -20282,6 +26456,21 @@ class basic_json
 
     /// @}
 };
+
+/*!
+@brief user-defined to_string function for JSON values
+
+This function implements a user-defined to_string  for JSON objects.
+
+@param[in] j  a JSON object
+@return a std::string object
+*/
+
+NLOHMANN_BASIC_JSON_TPL_DECLARATION
+std::string to_string(const NLOHMANN_BASIC_JSON_TPL& j)
+{
+    return j.dump();
+}
 } // namespace nlohmann
 
 ///////////////////////
@@ -20303,9 +26492,7 @@ struct hash<nlohmann::json>
     */
     std::size_t operator()(const nlohmann::json& j) const
     {
-        // a naive hashing via the string representation
-        const auto& h = hash<nlohmann::json::string_t>();
-        return h(j.dump());
+        return nlohmann::detail::hash(j);
     }
 };
 
@@ -20313,7 +26500,7 @@ struct hash<nlohmann::json>
 /// @note: do not remove the space after '<',
 ///        see https://github.com/nlohmann/json/pull/679
 template<>
-struct less< ::nlohmann::detail::value_t>
+struct less<::nlohmann::detail::value_t>
 {
     /*!
     @brief compare two value_t enum values
@@ -20326,20 +26513,25 @@ struct less< ::nlohmann::detail::value_t>
     }
 };
 
+// C++20 prohibit function specialization in the std namespace.
+#ifndef JSON_HAS_CPP_20
+
 /*!
 @brief exchanges the values of two JSON objects
 
 @since version 1.0.0
 */
 template<>
-inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcept(
-    is_nothrow_move_constructible<nlohmann::json>::value and
+inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcept( // NOLINT(readability-inconsistent-declaration-parameter-name)
+    is_nothrow_move_constructible<nlohmann::json>::value&&  // NOLINT(misc-redundant-expression)
     is_nothrow_move_assignable<nlohmann::json>::value
-)
+                              )
 {
     j1.swap(j2);
 }
 
+#endif
+
 } // namespace std
 
 /*!
@@ -20355,6 +26547,7 @@ if no parse error occurred.
 
 @since version 1.0.0
 */
+JSON_HEDLEY_NON_NULL(1)
 inline nlohmann::json operator "" _json(const char* s, std::size_t n)
 {
     return nlohmann::json::parse(s, s + n);
@@ -20373,6 +26566,7 @@ object if no parse error occurred.
 
 @since version 2.0.0
 */
+JSON_HEDLEY_NON_NULL(1)
 inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t n)
 {
     return nlohmann::json::json_pointer(std::string(s, n));
@@ -20381,26 +26575,179 @@ inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std
 // #include <nlohmann/detail/macro_unscope.hpp>
 
 
-// restore GCC/clang diagnostic settings
-#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
-    #pragma GCC diagnostic pop
-#endif
+// restore clang diagnostic settings
 #if defined(__clang__)
-    #pragma GCC diagnostic pop
+    #pragma clang diagnostic pop
 #endif
 
 // clean up
+#undef JSON_ASSERT
 #undef JSON_INTERNAL_CATCH
 #undef JSON_CATCH
 #undef JSON_THROW
 #undef JSON_TRY
-#undef JSON_LIKELY
-#undef JSON_UNLIKELY
-#undef JSON_DEPRECATED
+#undef JSON_PRIVATE_UNLESS_TESTED
+#undef JSON_HAS_CPP_11
 #undef JSON_HAS_CPP_14
 #undef JSON_HAS_CPP_17
+#undef JSON_HAS_CPP_20
 #undef NLOHMANN_BASIC_JSON_TPL_DECLARATION
 #undef NLOHMANN_BASIC_JSON_TPL
-
-
-#endif
+#undef JSON_EXPLICIT
+#undef NLOHMANN_CAN_CALL_STD_FUNC_IMPL
+
+// #include <nlohmann/thirdparty/hedley/hedley_undef.hpp>
+
+
+#undef JSON_HEDLEY_ALWAYS_INLINE
+#undef JSON_HEDLEY_ARM_VERSION
+#undef JSON_HEDLEY_ARM_VERSION_CHECK
+#undef JSON_HEDLEY_ARRAY_PARAM
+#undef JSON_HEDLEY_ASSUME
+#undef JSON_HEDLEY_BEGIN_C_DECLS
+#undef JSON_HEDLEY_CLANG_HAS_ATTRIBUTE
+#undef JSON_HEDLEY_CLANG_HAS_BUILTIN
+#undef JSON_HEDLEY_CLANG_HAS_CPP_ATTRIBUTE
+#undef JSON_HEDLEY_CLANG_HAS_DECLSPEC_DECLSPEC_ATTRIBUTE
+#undef JSON_HEDLEY_CLANG_HAS_EXTENSION
+#undef JSON_HEDLEY_CLANG_HAS_FEATURE
+#undef JSON_HEDLEY_CLANG_HAS_WARNING
+#undef JSON_HEDLEY_COMPCERT_VERSION
+#undef JSON_HEDLEY_COMPCERT_VERSION_CHECK
+#undef JSON_HEDLEY_CONCAT
+#undef JSON_HEDLEY_CONCAT3
+#undef JSON_HEDLEY_CONCAT3_EX
+#undef JSON_HEDLEY_CONCAT_EX
+#undef JSON_HEDLEY_CONST
+#undef JSON_HEDLEY_CONSTEXPR
+#undef JSON_HEDLEY_CONST_CAST
+#undef JSON_HEDLEY_CPP_CAST
+#undef JSON_HEDLEY_CRAY_VERSION
+#undef JSON_HEDLEY_CRAY_VERSION_CHECK
+#undef JSON_HEDLEY_C_DECL
+#undef JSON_HEDLEY_DEPRECATED
+#undef JSON_HEDLEY_DEPRECATED_FOR
+#undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_CAST_QUAL
+#undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_
+#undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_DEPRECATED
+#undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_CPP_ATTRIBUTES
+#undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNKNOWN_PRAGMAS
+#undef JSON_HEDLEY_DIAGNOSTIC_DISABLE_UNUSED_FUNCTION
+#undef JSON_HEDLEY_DIAGNOSTIC_POP
+#undef JSON_HEDLEY_DIAGNOSTIC_PUSH
+#undef JSON_HEDLEY_DMC_VERSION
+#undef JSON_HEDLEY_DMC_VERSION_CHECK
+#undef JSON_HEDLEY_EMPTY_BASES
+#undef JSON_HEDLEY_EMSCRIPTEN_VERSION
+#undef JSON_HEDLEY_EMSCRIPTEN_VERSION_CHECK
+#undef JSON_HEDLEY_END_C_DECLS
+#undef JSON_HEDLEY_FLAGS
+#undef JSON_HEDLEY_FLAGS_CAST
+#undef JSON_HEDLEY_GCC_HAS_ATTRIBUTE
+#undef JSON_HEDLEY_GCC_HAS_BUILTIN
+#undef JSON_HEDLEY_GCC_HAS_CPP_ATTRIBUTE
+#undef JSON_HEDLEY_GCC_HAS_DECLSPEC_ATTRIBUTE
+#undef JSON_HEDLEY_GCC_HAS_EXTENSION
+#undef JSON_HEDLEY_GCC_HAS_FEATURE
+#undef JSON_HEDLEY_GCC_HAS_WARNING
+#undef JSON_HEDLEY_GCC_NOT_CLANG_VERSION_CHECK
+#undef JSON_HEDLEY_GCC_VERSION
+#undef JSON_HEDLEY_GCC_VERSION_CHECK
+#undef JSON_HEDLEY_GNUC_HAS_ATTRIBUTE
+#undef JSON_HEDLEY_GNUC_HAS_BUILTIN
+#undef JSON_HEDLEY_GNUC_HAS_CPP_ATTRIBUTE
+#undef JSON_HEDLEY_GNUC_HAS_DECLSPEC_ATTRIBUTE
+#undef JSON_HEDLEY_GNUC_HAS_EXTENSION
+#undef JSON_HEDLEY_GNUC_HAS_FEATURE
+#undef JSON_HEDLEY_GNUC_HAS_WARNING
+#undef JSON_HEDLEY_GNUC_VERSION
+#undef JSON_HEDLEY_GNUC_VERSION_CHECK
+#undef JSON_HEDLEY_HAS_ATTRIBUTE
+#undef JSON_HEDLEY_HAS_BUILTIN
+#undef JSON_HEDLEY_HAS_CPP_ATTRIBUTE
+#undef JSON_HEDLEY_HAS_CPP_ATTRIBUTE_NS
+#undef JSON_HEDLEY_HAS_DECLSPEC_ATTRIBUTE
+#undef JSON_HEDLEY_HAS_EXTENSION
+#undef JSON_HEDLEY_HAS_FEATURE
+#undef JSON_HEDLEY_HAS_WARNING
+#undef JSON_HEDLEY_IAR_VERSION
+#undef JSON_HEDLEY_IAR_VERSION_CHECK
+#undef JSON_HEDLEY_IBM_VERSION
+#undef JSON_HEDLEY_IBM_VERSION_CHECK
+#undef JSON_HEDLEY_IMPORT
+#undef JSON_HEDLEY_INLINE
+#undef JSON_HEDLEY_INTEL_CL_VERSION
+#undef JSON_HEDLEY_INTEL_CL_VERSION_CHECK
+#undef JSON_HEDLEY_INTEL_VERSION
+#undef JSON_HEDLEY_INTEL_VERSION_CHECK
+#undef JSON_HEDLEY_IS_CONSTANT
+#undef JSON_HEDLEY_IS_CONSTEXPR_
+#undef JSON_HEDLEY_LIKELY
+#undef JSON_HEDLEY_MALLOC
+#undef JSON_HEDLEY_MCST_LCC_VERSION
+#undef JSON_HEDLEY_MCST_LCC_VERSION_CHECK
+#undef JSON_HEDLEY_MESSAGE
+#undef JSON_HEDLEY_MSVC_VERSION
+#undef JSON_HEDLEY_MSVC_VERSION_CHECK
+#undef JSON_HEDLEY_NEVER_INLINE
+#undef JSON_HEDLEY_NON_NULL
+#undef JSON_HEDLEY_NO_ESCAPE
+#undef JSON_HEDLEY_NO_RETURN
+#undef JSON_HEDLEY_NO_THROW
+#undef JSON_HEDLEY_NULL
+#undef JSON_HEDLEY_PELLES_VERSION
+#undef JSON_HEDLEY_PELLES_VERSION_CHECK
+#undef JSON_HEDLEY_PGI_VERSION
+#undef JSON_HEDLEY_PGI_VERSION_CHECK
+#undef JSON_HEDLEY_PREDICT
+#undef JSON_HEDLEY_PRINTF_FORMAT
+#undef JSON_HEDLEY_PRIVATE
+#undef JSON_HEDLEY_PUBLIC
+#undef JSON_HEDLEY_PURE
+#undef JSON_HEDLEY_REINTERPRET_CAST
+#undef JSON_HEDLEY_REQUIRE
+#undef JSON_HEDLEY_REQUIRE_CONSTEXPR
+#undef JSON_HEDLEY_REQUIRE_MSG
+#undef JSON_HEDLEY_RESTRICT
+#undef JSON_HEDLEY_RETURNS_NON_NULL
+#undef JSON_HEDLEY_SENTINEL
+#undef JSON_HEDLEY_STATIC_ASSERT
+#undef JSON_HEDLEY_STATIC_CAST
+#undef JSON_HEDLEY_STRINGIFY
+#undef JSON_HEDLEY_STRINGIFY_EX
+#undef JSON_HEDLEY_SUNPRO_VERSION
+#undef JSON_HEDLEY_SUNPRO_VERSION_CHECK
+#undef JSON_HEDLEY_TINYC_VERSION
+#undef JSON_HEDLEY_TINYC_VERSION_CHECK
+#undef JSON_HEDLEY_TI_ARMCL_VERSION
+#undef JSON_HEDLEY_TI_ARMCL_VERSION_CHECK
+#undef JSON_HEDLEY_TI_CL2000_VERSION
+#undef JSON_HEDLEY_TI_CL2000_VERSION_CHECK
+#undef JSON_HEDLEY_TI_CL430_VERSION
+#undef JSON_HEDLEY_TI_CL430_VERSION_CHECK
+#undef JSON_HEDLEY_TI_CL6X_VERSION
+#undef JSON_HEDLEY_TI_CL6X_VERSION_CHECK
+#undef JSON_HEDLEY_TI_CL7X_VERSION
+#undef JSON_HEDLEY_TI_CL7X_VERSION_CHECK
+#undef JSON_HEDLEY_TI_CLPRU_VERSION
+#undef JSON_HEDLEY_TI_CLPRU_VERSION_CHECK
+#undef JSON_HEDLEY_TI_VERSION
+#undef JSON_HEDLEY_TI_VERSION_CHECK
+#undef JSON_HEDLEY_UNAVAILABLE
+#undef JSON_HEDLEY_UNLIKELY
+#undef JSON_HEDLEY_UNPREDICTABLE
+#undef JSON_HEDLEY_UNREACHABLE
+#undef JSON_HEDLEY_UNREACHABLE_RETURN
+#undef JSON_HEDLEY_VERSION
+#undef JSON_HEDLEY_VERSION_DECODE_MAJOR
+#undef JSON_HEDLEY_VERSION_DECODE_MINOR
+#undef JSON_HEDLEY_VERSION_DECODE_REVISION
+#undef JSON_HEDLEY_VERSION_ENCODE
+#undef JSON_HEDLEY_WARNING
+#undef JSON_HEDLEY_WARN_UNUSED_RESULT
+#undef JSON_HEDLEY_WARN_UNUSED_RESULT_MSG
+#undef JSON_HEDLEY_FALL_THROUGH
+
+
+
+#endif  // INCLUDE_NLOHMANN_JSON_HPP_